VOL 1
WATER NEW ZEALAND
Good Practice Guide
FLUORIDATION OF
DRINKING-WATER
SUPPLIES IN
NEW ZEALAND
February 2023
ISBN NUMBER: 978-0-473-65595-2

Copyright ©
Reproduction, adaptation or issuing of this publication for educational or other non-commercial
purposes is authorised without prior permission of the Water New Zealand. Reproduction,
adaptation or issuing of this publication for resale or other commercial purposes is prohibited without the prior
permission of Water New Zealand.
Disclaimer
Water New Zealand, Beca and individual contributors are not responsible for the results of any actions taken
on the basis of information in this guideline. Water New Zealand make no representation or warranty of any
kind, whether expressed or implied, concerning the product, accuracy or process discussed in this guideline
and assumes no liability arising from such use.

Foreword
Fluoride is added to drinking water to help protect against tooth decay. The Health Act grants the Director-
General of Health decision making powers on community water fluoridation. Water suppliers wil  be
required to fluoridate a water supply if directed to do so by the Director-General of Health. Those already
fluoridating are required to continue to do so.
This guide has been developed to assist water suppliers in the design and operation of water fluoridation
plants to enable ef ective addition of fluoride to water supplies in a manner which protects public health,
and the operators who maintain them.
Formerly Water New Zealand had published a Code of Practice for Fluoridation of Drinking-water Supplies
in New Zealand and the Good Practice Guide for Supply of Fluoride for Use in Water Treatment. Since this
time the passing of the Health (Fluoridation) Amendment Act, and new Drinking Water Quality Assurance
Rules, published by Taumata Arowai, New Zealand’s drinking water regulator, both of which have shifted
the roles and responsibilities in relation to the fluoridation of drinking water supplies. This Good Practice
Guide has therefore been updated to ensure guidance on the fluoridation of water supplies reflects this
shift.
The Code of Practice for Fluoridation of Drinking-water Supplies, was developed in conjunction with the
Ministry of Health, supported by Victorian Department of Health, and received important contributions from
a wide range of water suppliers and industry stakeholders. The Code of Practice specified optimum fluoride
levels for drinking-water supplies as defined by the Ministry of Health and the design control limits for
fluoridation plants, for safe and effective addition of fluoride into a drinking-water supply. Volume 1 of this
guideline maintains the fluoride dose and control limits established in the Code of Practice.
Additionally, a Design Guidance document (Volume 2 of this Good Practice Guide) has been prepared b, in
consultation with chemical, equipment and water suppliers.  The content of Volume 2 reflects industry
feedback on the most effective materials and means to achieve the safe and ef ective design and operation
of drinking water fluoridation.
The Good Practice Guide for Supply of Fluoride  for Use in Water Treatment was developed to provide
purchasers, manufacturers and suppliers with minimum requirements for the physical, chemical and testing
requirements for fluoride at the point of supply. Since then, Taumata Arowai has introduced Chemical Rules
outlined in the Drinking Water Quality Assurance Rules, which provide new testing requirements for fluoride.
Specific Impurity Limits for product testing using the approach developed in the Good Practice Guide for
Supply of Fluoride for Use in Water Treatment are listed in Volume 2, Appendix A of this guide.
While there is no legal requirement to comply with these guidelines, they represent industry- endorsed good
practice. If complied with, these guidelines provide a means of ensuring risks association with fluoridation
in the water supply are satisfactorily mitigated. We encourage all water suppliers undertaking fluoridation
to adopt the good practices outlined in these guidelines.



  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             1

Acknowledgements
These  guidelines have been produced in two volumes, both building on a significant body of industry
experience and previous industry guidance.
Volume 1 of the Guide draws on the “Code of Practice for Fluoridation of Drinking-water Supplies”. Updates
to content were provided by Andrew Watson, Phil ip Roche and Sarah Burgess of Beca, and funded by the
Ministry of Health. This work develops on the significant body of work that went into the original code
development, developed in conjunction with Ministry of Health, drawing on knowledge from the Victorian
Department of Health, and receiving contributions from a broad range of industry stakeholders.
Volume 2 of the Guide has been authored by Iain Rabbits of Lutra, with support from Ciaran Hyland, with
funding provided by the Water Service Managers Group. The guide draws on Lutra’s experience designing
fluoridation plants across New Zealand. Seaton Rol eston at IXOM and Mark Harrison at ChemFeed
provided practical advice on products and material that fed into the guides development. Noah Hensley of
Taumata Arowai, provided guidance on how fluoride wil  be managed under the new regulatory regime.
John MacAndrew and Derek Crawford of Dunedin City Council provided suggestions on the types of
information needed by water suppliers to manage fluoride dosing at water treatment plants.
“The Good Practice Guide for Supply of Fluoride Use in Water Treatment” impurity limits have also informed
this guide. Product impurity limits set in the Good Practice Guide, and outlined in Volume 2, Appendix A of
this document, were calculated by Chris Nokes, then employed by ESR, with review of several water and
chemical suppliers.  The specific impurity limits were updated to reflect any new maximum acceptable
values by Iain Rabbitts
Water New Zealand wishes to acknowledge the authors of this document, previous fluoridation guidance,
and the many contributors to past and present versions of their guides for their contribution to ensuring the
safe and effective fluoridation of New Zealand’s water supplies.



  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             2

Abbreviations
Terms
Description
DWQAR
Drinking Water Quality Assurance Rules
FSA
Fluorosilicic Acid (see table 1 for other acronyms)
HACCP
Hazard analysis critical control point
HAZOP
Hazard and operability study
ISE
ion-selective electrode
MAV
Maximum Al owable Value
MSDS
Material Safety Data Sheet
Na2[SiF6]
Sodium silicofluoride
NaF
Sodium fluoride
SIL
Specific impurity limit
TISAB
Total Ionic Strength Adjustment Buffer


  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             5

1  Introduction
Fluoridation is undertaken by drinking-water suppliers either as the result of a “Direction to Fluoridate” by
the Director-General of Health, or at the supplier’s discretion. The optimal range for oral health is in the
range of 0.7 to 1.0 mg/L, as recommended by the Ministry of Health.  The Good Practice Guide for the
Fluoridation of Drinking-Water Supplies (this Guide) specifies good practice for the safe design and effective
operation of a fluoridation plant.
Safe and ef ective fluoridation of drinking-water supplies requires the adoption of a preventive risk
management approach in the design and operation of fluoridation plants. Preventive risk management
systems are the most effective way to assure the safe and effective addition of fluoride into a drinking-water
supply. These systems underpin the approach taken in Water Safety Plans.
This guide is presented in two parts. The first volume covers the regulatory framework and specifies the
minimum requirements for designing, operating and monitoring drinking-water fluoridation systems. The
second separate volume presents guidance for the detailed design of the storage and dosing of the three
alternative fluoridation chemicals used in New Zealand.
1.1
Objectives
The overall objective of this Guide  is to ensure  safe and ef ective addition of fluoride into a drinking-
water supply.
The purpose of Volume 1 is to specify:
•  Optimum fluoride levels for drinking-water supplies as defined by the Ministry of Health and the
design control limits for fluoridation plants.
•  Minimum requirements for the safe and effective addition of fluoride chemicals to drinking-water
supplies, covering the design and operation of a fluoridation plant.
•  Monitoring and reporting requirements for fluoridation.
The purpose of Volume 2 is to provide guidance for the design, storage and delivery control of fluoridation
systems, that wil  fulfil these requirements, by providing:
o  Piping and instrumentation diagrams for equipment
o  Guidance on equipment sizing
o  Information on materials selection operations and considerations
o  Specific Impurity Limits for contaminants  to ensure  Maximum Al owable Values  are not
exceeded.



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1.2
Scope
This guide is applicable to the design of all new and existing fluoride plants from the date of publication.
Volume 1 covers:
•  The regulatory framework (Section 2)
•  Safety in design (Section 3)
•  Minimum requirements for the design and control of fluoridation facilities (Section 4)
•  Minimum requirements for plant operation including monitoring, training of personnel, occupational
health and safety, security and environmental protection (Section 5).
Volume 2 covers:
•  Chemical Selection (Section 2)
•  Fluorosilicic acid (Hydrofluorosilic acid) Design (Section 3)
•  Sodium fluorosilicate (Sodium Silicofluoride) Design (Section 4)
•  Sodium Fluoride Saturator System Design (Section 5)
•  Specific Impurity Limits (Appendix A).
1.3
Terminology
Good Practice Guide for the Fluoridation of Drinking-Water Supplies: ‘this Guide’
Drinking-water Supplier: The Water Services Act (2021) defines a drinking-water supplier as a person who:
a)  supplies drinking water to people through a drinking water supply, and
b)  includes a person who ought reasonably to know that the water they are supplying is or wil  be used as
drinking water; and
c)  includes the owner and the operator of a drinking water supply; and
d)  includes a person described in paragraph (a), (b), or (c) who supplies drinking water to another drinking
water supplier; but
e)  does not include a domestic selfsupplier.

Water Services (Drinking Water Standards for New Zealand) Regulations 2022: ‘the DWSNZ’
Fluoride concentration: The fluoride concentration refers to the total amount of fluoride ion  present
regardless of its form and is expressed in mil igrams per litre (mg/L) (Note: 1 mg/L = 1 g/m3 = 1 ppm (w/v)).
Fluoridation plant: The building and equipment required for fluoridation of drinking-water, including
chemical storage and unloading areas, dosing and control equipment, safety equipment and other fixtures
used for, or associated with, the purpose of fluoridation.
Guidelines for Drinking-water Quality Management for New Zealand: Guidelines to help water suppliers to
comply with the Water Services Act.
Health and Safety at Work (Hazardous Substances) Regulations 2017  (Hazardous Substances Regulations).'


  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             7

Health Act 1956: The Act that enables the Director-General of Health to direct a local authority to add
fluoride or not to add fluoride to drinking water supplies.
Safeguards:  A suite of six requirements that all must be in place to minimise the risk of overdosing of
fluoride (refer section 4.4)
Maximum Acceptable Value: 'MAV' as defined by the Water Services (Drinking Water Standards for New
Zealand) Regulations 2022
‘Must’ and ‘should’
The word ‘must’ identifies a mandatory requirement for compliance with this Guide.
The word ‘should’ refers to practices that are advised or recommended but are not mandatory for
compliance with this Guide.


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2  Regulatory Framework
This section outlines legislative requirements of relevance to the management of water fluoridation.
2.1
Legislation
2.1.1
Health (Fluoridation of Drinking Water) Amendment Act 2021
‘The Health (Fluoridation of Drinking Water) Amendment Act 2021 shifted decision-making on fluoridation
from water suppliers to the Director-General of Health. The change allows for a nationally-consistent
approach to community water fluoridation based on its health benefits.
Water suppliers wil  be required to fluoridate a water supply if directed to do so by the Director-General of
Health. Those already fluoridating are required to continue to do so.
In deciding whether to make a direction to fluoridate, the Director-General of Health is required to consider:
•  scientific evidence on the effectiveness of adding fluoride to drinking water in reducing the
prevalence and severity of dental decay
•  whether the benefits of adding fluoride to drinking water outweigh the costs, including consideration
of local oral health status, population numbers, and financial cost.
2.1.2
Water Services Act 2021
The Water Services Act provides a drinking water regulatory framework to ensure that safe drinking water
supplies are provided to consumers. The act gives Taumata Arowai the legal authority to carry out its duties
as New Zealand’s dedicated water regulator.  Taumata Arowai are the water services regulator for
Aotearoa New Zealand, responsible for developing regulatory instruments (such as Rules, Standards and
Acceptable Solutions).
Taumata Arowai publish Drinking Water Standards and Drinking Water Quality Assurance Rules. The
Drinking Water Quality Assurance Rules (Rules) set out what drinking water suppliers need to do to comply
with key parts of the Drinking Water Standards and the Water Services Act 2021 and set monitoring
requirements that apply to fluoride.
2.1.3
Water Services (Drinking Water Standards for New Zealand) Regulations 2022
These regulations, which come into force on 14 November 2022, set the Drinking Water Standards for New
Zealand. The standards set limits for the concentration of determinands in drinking water. The limits are
referred to as maximum acceptable values (MAVs) including fluoride. The MAVs for any determinand must
not be exceeded at any time.
2.1.4
Other Relevant Legislation
•  Health Act 1956 (2022)
•  Health and Safety at Work Act 2015
•  Health and Safety at Work (Hazardous Substances) Regulation 2017
•  General Risk And Workplace Management Regulations 2017.


  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             9

•  Local Government Act 2002
2.1.5
Other relevant standards
In addition to ensuring that the design, construction and operation of the fluoridation plant complies with
the relevant legislative requirements, additional standards relevant to the operation of fluoride plants
include, but are not limited to:
  Code of Practice HSNOCOP 47 Secondary Containment System
  NZS/AS 1319-1994 Safety signs for the occupational environment
  AS 1345-1995 Identification of the contents of pipes, conduits and ducts
  AS/NZS 1715-2009 Selection, use and maintenance of respiratory protective devices
  AS 3780:2008 The storage and handling of corrosive substances (class 8 and 6)
  AS/NZS 4020:2018 Testing of products for use in contact with drinking water
  AS/NZS 4360:2004 Risk management
  ISO 9001:2015, ISO 14001:2015,  Quality management and environmental hazard control systems
  AS/NZS 4452:1997 The storage and handling of toxic substances
  AS/NZS 4801:2001 Occupational health and safety management systems
  NZS 5807:1980 Code of practice for industrial identification by colour, wording or identification
  NZS 5433:2020 Transport of Dangerous Goods on Land
  Code of Practice for Manual Handling, Published jointly by the Occupational Safety and Health
Service of the Department of Labour and the Accident Compensation Corporation. June 2001
  Trade Waste Bylaws (if disposing of fluoride wastes to Council wastewater systems)
  Workplace Exposure Standards and Biological Exposure Indices published by Worksafe.
2.2  Drinking Water Safety Plans
A Drinking Water Safety Plan requires a drinking-water supplier to consider the potential risks to the water
supply and identify ways to manage these risks and is therefore prepared for any problems that may arise.
Al  water suppliers are required to have a Drinking Water Safety Plan. Documentation of compliance with
the safeguard requirements of Volume 1 of this Guide is deemed to meet the risk assessment requirements
of the Drinking Water Safety Plan in relation to fluoridation.
2.3  This Guide
This Guide describes good practice for drinking-water fluoridation. While there is no legal requirement to
comply with this Guide, it consolidates good practice from the New Zealand water industry. It therefore
represents an industry-endorsed Guide and, if complied with, a means of documenting in the Drinking Water
Safety Plan that the risks associated with fluoridation in the supplier's water supply plant have been
satisfactorily mitigated.
The Guide has been written to assist water-suppliers in designing a new drinking-water fluoridation system
or upgrading an existing system to ensure the safety of its consumers.



  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             10

2.4  Roles and responsibilities
2.4.1
Taumata Arowai
Taumata Arowai is the water services regulator for New Zealand. Their function is to regulate the provision
of drinking-water services and protect public health by ensuring communities receive safe drinking-water.
They regulate drinking water safety through the use of Quality Assurance Rules, Quality Standards and
Aesthetic Guideline Values. Water suppliers who fluoridate need to make sure that they comply with these
requirements.
2.4.2
Manatū Hauora - Ministry of Health
The function of Manatū Hauora is improving, promoting, and protecting public health. The Director-General
of Health has powers under the Health (Fluoridation of Drinking Water) Amendment Act 2021 to direct
drinking-water suppliers to add or not add fluoride to drinking-water supplied by them. Water suppliers that
were adding fluoride to their drinking-water supply prior to the commencement of the Amendment Act must
continue to add fluoride to their drinking-water supplies unless directed not to do so by the Director-General
of Health. Water suppliers are also encouraged to add fluoride to their drinking water supplies in the
absence of a direction. The addition of fluoride to drinking-water in the range 0.7 - 1 mg/L is a safe, effective,
and affordable way to prevent and reduce tooth decay across the whole population.
2.4.3
Drinking-water Supplier
For new and upgraded fluoridation plants, drinking-water suppliers are recommended to design, construct
and operate the fluoridation plant in accordance with this Guide.
The drinking-water supplier is responsible for ensuring that the design, installation and operation of the
fluoridation plant, and the storage and handling of chemicals, are in accordance with al  the relevant
legislative requirements. Specifically, the drinking-water supplier must ensure that the water fluoridation
plant is incorporated into the Drinking Water Safety Plan for a drinking-water supply.
Prior to the construction of a fluoridation plant, the drinking-water supplier should have the design peer-
reviewed against this Good Practice Guide, to demonstrate that the plant wil  operate in a safe and effective
manner.
In relation to transport of chemicals, the drinking-water supplier is responsible for engaging contractors who
comply with relevant legislative requirements. Shipping of the chemicals, unloading and storage should be
in accordance with the Water New Zealand, Good Practice Guide: Supply of Fluoride for Use in Water
Treatment.
Drinking-water suppliers must be able to demonstrate they are not exceeding the MAV for fluoride  to
Taumata Arowai and that they are meeting the optimal range for fluoridation to Manatū Hauora. At the time
of publishing this Guide, Manatū Hauora is developing a process for suppliers to demonstrate that fluoride
is being provided within the optimal range. Compliance with these requirements is beyond the scope of this
Guide.


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3  Safety in Design
3.1
Approach
The Safety in Design process involves the application of a risk management framework early in the design
process to eliminate or minimise the risk to public health and the environment and to ensure occupational
health and safety throughout the life of the fluoridation plant. It encompasses all phases of the plant design
including facilities, hardware, systems, equipment, products, tooling, materials, energy controls, layout and
configuration.  The  Health and Safety at Work Act 2015  requires  designers  to, as far as is reasonably
practicable, make sure that structures, plant or substances to be used in a workplace are without health
and safety risk, among other duties.
In the context of water fluoridation, Safety in Design encompasses:
•  Drinking-water safety for consumers
•  Occupational health and safety
•  Environmental safety
A safe design basis, together with a formal safety management system and safety practices, procedures,
and training, is critical for providing the level of confidence required.
3.2   Risk assessment
Drinking water suppliers that are fluoridating or are planning on installing new plant to fluoridate must carry
out and document a site-specific risk assessment covering all aspects of safety and environmental risk
associated with the design and operation of the fluoridation plant. Where risks are identified, appropriate
control measures (based on the hierarchy of controls) must be implemented. The preventive risk
management system must include the development of considered and control ed responses to incidents or
emergencies that can compromise the safety of fluoridating a drinking-water supply, worker safety or
the environment.
Based on the hierarchy of controls, hazards should be eliminated wherever practicable, fol owed by
minimising the remaining hazards through use of engineering controls.
The risk assessment for the fluoridation plant and the effectiveness of actual control measures should be
reviewed on a regular basis. Initial  design risk control measures should not be degraded through
subsequent modifications of the fluoridation plant and/or the water supply system.
This is consistent with the approach taken in Drinking Water Safety Plans.
3.2.1
Risk-based systems
Risk-based systems include ISO 9001, ISO 14001, HACCP and local standards such as the Australian and
New Zealand Risk management standard (AS/NZS 4360). A risk-based system must be used to
systematically address and manage risks associated with the fluoridation plant prior to commissioning.


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3.2.2
Hazard and operability (HAZOP) studies
Hazard and Operability (HAZOP) studies are conducted by water suppliers as one part of the Safety in
Design assessment. The HAZOP should involve the application of a formal systematic critical examination
of the process and engineering intentions of the fluoridation plant to assess the hazard potential of
inappropriate operation or malfunction of individual items of equipment and their consequential effects on
the water treatment plant as a whole.
Any actions arising from the HAZOP study should be incorporated into the design and/or operation of the
fluoridation plant.
3.3  Drinking-water safety
The performance objective is to ensure the design, construction, installation, operation, and maintenance
of the fluoridation plant promotes and protects public health by:
•  Maintaining the optimum fluoride concentration in the drinking-water supply
•  Minimising the risk of overdosing of fluoride
•  Implementation of quality assurance processes to guarantee the chemical purity of the fluoridating
agent.
Controls for managing risks to drinking-water safety, as identified through the site-specific risk assessment,
should be incorporated in the drinking-water supplier’s Drinking Water Safety Plan.
3.4  Occupational Health and Safety
The design and operation of the fluoridation plant must ensure worker safety. The drinking-water supplier
must conduct and document a site-specific safety hazard risk assessment covering all aspects associated
with the design and operation of the fluoridation plant.
It is the responsibility of the  drinking-water supplier to  ensure risks are assessed and managed in
accordance with the relevant occupational health and safety requirements. The Health and Safety at Work
Act 2015  provides information and advice on eliminating hazards and control ing risks at the design,
construction and operational stage to those involved in the design or modification of products, and
processes used for work. Health monitoring of staff must be carried out to ensure that the hazard risk
controls employed are functioning as intended. This is an employer responsibility required under the
Workplace Exposure Standards and Biological Exposure Indices.



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link to page 16
4  Design of Fluoridation Plant
4.1
Fluoridation chemical types and selection
The three chemicals used for the fluoridation of drinking-water in New Zealand are listed in Table 1.
Each chemical has dif erent storage, handling, delivery and dosing requirements, dif erent chemicals are
suitable  for dif erent applications.  Chemical selection considerations are outlined in Volume 2 of this
guideline.
Evidence of the selection process (including a risk assessment) should be recorded.
Table 1: Fluoridating agents
Common
Formula
CAS No.*
Alternative
UN Class
Hazard
name
name(s)
Classification**
Fluorosilicic
H2SiF6
1696183
Hydrofluorosilicic
8, PG II
8.2C, 8.3A
Acid (FSA)
4
acid (HFA),
hexafluorosilicic
acid
Sodium
NaF
7681494
Sodium
6.1; PG III
6.1C, 6.3A,
fluoride
monofluoride
6.4A, 6.6B,
6.8B, 6.9A,
9.1D, 9.3B
Sodium
Na2SiF6
1689385
Sodium
6.1; PG III
6.1C, 6.4A,
fluorosilicate
9
silicofluoride
9.3B
(SFS)
(SSF), sodium
hexafluorosilicate
* CAS Numbers are as per the Chemical Classification and Information Database (CCID) on
www.epa.govt.nz. Note that there are other CAS numbers in use for these chemicals.
** Classification as per the CCID on www.epa.govt.nz (chemicals in the CCID are classified in accordance
with the Hazardous Substances and New Organisms (HSNO) regulations)
Volume 2 Appendix  A of this  Good Practice Guide outlines  the appropriate specification limits for
contaminants using the Maximum Acceptable Value (MAV) approach of the DWSNZ.
Undertaking a risk assessment wil  enable drinking water suppliers to ensure that any material used
in the dosing of fluoride, such as soluble bags1, do not present a risk to public health. The risk
assessment should also cover the addition of contaminants in the fluoridation chemical, combined with
the concentrations of these contaminants already present in the supply, to ensure these do not result
in any contaminant exceeding its MAV.

1 Note that soluble bags, which are available in Australia for sodium fluoride, are not currently available in
New Zealand.


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4.2  Concentration of fluoride in water
The purpose of fluoridation is to adjust the natural fluoride content of drinking-water to the optimum level
to provide a dental health benefit. Dosing fluoride into drinking-water is a continuous process with the
objective of providing a lifetime exposure to fluoride for all consumers. The target concentration of fluoride
in treated water is 0.85 mg/L, with variation between 0.7 and 1.0 mg/L al owed.
The dosing concentration (including allowance for the fluoride concentration in the raw water) should be
included in the Drinking Water Safety Plan. The drinking-water supplier should maintain a historical record
of the fluoride concentration in the raw water to ensure an appropriate allowance is made for the fluoride
concentration in determining the dosing concentration. The fluoride concentration in the raw water should
be analysed at an appropriate frequency for the expected variability.
4.3  Design control limits
The design of the fluoridation plant should:
•
Use the fluoride target dosing concentration as specified in Table 2 and be control ed to the limits
specified in Table 2.
•
At no time allow the fluoride concentration in the drinking-water supply to exceed the MAV,
specified n the Water Services (Drinking Water Standards for New Zealand) Regulations 2022).  At the time
of publication this is set at 1.5 mg/L.
Safeguards linked to an appropriate alarm monitoring system and automatic shut-down, are required refer
section 4.4. The fluoride plant control limits in Table 2 apply specifically to the instruments used for real-
time fluoride monitoring, namely those instruments used for calculating instantaneous water flow and
fluoride dose rates, and analyser/s for monitoring the fluoride concentration, if fitted.
Any delay time associated with the process limits in Table 2 (to account for instantaneous spikes) should
be kept to a minimum, justified, and documented.
Table 2: Fluoride plant control limits and alarms
Total fluoride ion
concentration
Parameter
(mg/L)
Response to process limits
Operating target (to be achieved for ≥95%
0.85 mg/L.

of the time that the treatment plant is
producing water)
Operating range (≥95% of the time that the
Within ± 0.15 of
–
fluoridation plant is in operation)
operating target.



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Upper action process limit
1.3^
Immediate fluoride plant shut down
(safeguards must be interlocked with the
dosing system.)
Emergency limit
1.5†
Immediate fluoride plant shut down.
(Safeguards must be interlocked with the
dosing system.) Notify Taumata Arowai,
investigate the cause of the exceedance and
take appropriate action.
*
NHMRC 2007, A systematic review of the efficacy and safety of fluoridation
^
This action level is a slightly lower dose than the maximum level of fluoride permitted in the DWSNZ, and has been established to
minimise the risk that the MAV is exceeded.
†
Based on the Maximum Acceptable Value set in Water Services (Drinking Water Standards for New Zealand) Regulations 2022.

4.4   Safeguards
Overdosing of fluoride chemicals can lead to adverse health effects to consumers, as well as a loss of
confidence in the safety of a supply. The fol owing safeguards (A, B, C, D, E and F) must be in place for al
fluoride dosing systems  as a minimum.  Volume 2 outlines design guidance that  provides for these
safeguards.
A)  Flow Proportional Dosing
Dosing shall be control ed in proportion to the measured water flow at the fluoride chemical dose
point. Refer Section 4.7.5 for detailed requirements for flow measurement.
B)  Dosing Capacity Limit
The maximum physical dosing capacity of the fluoridation chemical feeding equipment must be
limited by design to a maximum value that is as close as practicable to the operating target dose
rate at the maximum water flow rate. This maximum value should not exceed 110 per cent of the
operating target dose rate at the maximum plant capacity. For metering pumps which have a
manual stroke adjustment, the component of the dosing flow that is able to be changed by manual
adjustment of the stroke is excluded from this requirement, as long as the stroke adjustment is
locked in position and its maximum operating position is clearly marked.  Means shall be provided
to enable the calibration of the dose pump.
C)  Flow Measurement at Dose Point
Dosing should only operate when a positive water flow is measured at the point where the fluoride
chemical is dosed.  Two independent means should be used to verify water flow for large supplies
(> 500 people).  A flow switch, that reliably switches at an intermediate flow between the plant
minimum flow and zero flow may be used as one of these for large supplies that require a second
independent means.
Note serious overdosing events have occurred as a result of errant flow signals, including where a
pipeline was drained, causing the flow meter to send random flow signals – such risks should be
considered as part of the risk analysis.


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Note that the HAZOP should consider the risks of failure to shut off fluoride supply on plant stop,
and in particular where the dose point is at a lower level than the dose tank whether a loading
valve provides sufficient safeguard or whether a more positive shut off such as an actuated valve
is warranted.
D)   Day Tank Mass/Volume Monitoring.
Fluoride is dosed from a day tank (applicable to fluorosilicic acid or sodium fluoride), or day hopper
(SFS).
The total volume of the day tank/hopper shall not exceed 110% of the volume of chemical that would
be dosed in a day at the maximum capacity of the treatment plant.
Chemical may be transferred to the day tank more than once every 24 hours if a proportionally
smaller tank is designed for. For example, the design period for transfers could be every 12 hours,
in which case the tank/hopper volume shall be less than 110% of the volume expected to be used
at the maximum capacity of the treatment plant in 12 hours.
The day tank/hopper must be equipped with either an online weight measurement device or an
online level instrument (level only applicable to liquid chemical solutions) that enables
measurement of the quantity of fluoride used during each 24-hour period (or lesser design period).
Accuracy of the level/weight measurement shall be to better than ± 1% of the range being
measured.
The quantity of fluoride used each day provides an independent check of the amount of fluoride
chemical dosed.
Transfer must not occur more frequently than the design period (i.e. 24 hours, or less if the design
period selected is less than 24 hours).
Transfer should occur through control ed transfer.  Safety measures shall be considered in the
HAZOP. Gravity transfer should be prevented by appropriate design. An anti-siphon loop or
positioning the dose tank below the day tank is preferred, however an actuated valve is acceptable.
E)  Treated Water Fluoride Analysis
Online monitoring of the fluoride concentration in the fluoride dosed water shall be undertaken.
Note this requirement over rides the DWQAR T1 and T2 rule in which on line analysis is not required.
Refer to Section 4.7.6 for detailed requirements.
F)  Treated Water Storage
There shall be a storage tank between the dose point and any consumer, in order to buffer short
term concentration variations.  This tank shall have a minimum 15 minutes nominal hydraulic
retention time at maximum flow.



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link to page 28 link to page 17 link to page 17 link to page 16
4.5  Functionality of the fluoridation plant
4.5.1
Design requirements
The fluoridation plant must be designed to meet the fol owing requirements as well as the Safeguards
specified in Section 4.4:
a)
The design of the fluoridation plant must ensure that provision is made for operational staf  to
operate, monitor control, and maintain the fluoridation process safely, reliably, accurately and in a timely
manner. Refer Section 5.5 for health & safety measures for consideration during design.
b)
The fluoride concentration in the water supplied for drinking must comply with the requirements set
out in Sections 4.3 and 4.4.
c)
The plant must be configured so that all the functionality requirements set out in Section 4 are fully
automated, and operated by a control system that is based at the treatment plant.
d)
Plant design must ensure dependable automatic operation with reliable stopping and starting of
the system during plant shut-down and start-up.
e)
The plant must have alarms (including after hours to duty operator) and automatic shut-downs for
key process elements.
f)
The drinking-water supplier must ensure that upon failure of the control system, treated water
exceeding the emergency process limit in Table 2 does not enter the drinking-water supply system. This
fail safe system would include metering pumps  stopping and fluoride  supply valves closing  (where
applicable).
g)
Metering pumps should be in a duty/standby arrangement. A duty/assist arrangement is
acceptable, however the additional risk of control malfunctions must be considered.
This is not an all-inclusive list and further functionality requirements may be identified in the HAZOP and/or
the safety-in-design phases. Alternatives may be used, as long as an equivalent level of safety, control and
risk minimisation can be demonstrated and signed of  as part of the peer review of the design.
4.5.2
Other design considerations
a)
Anti-siphonage, back-flow protection and pressure relief
The dosing system must be fitted with an anti-siphon valve.
Any water supply used for dissolving the fluoridating agent or as carry water must have a backflow
prevention device fitted upstream of where the fluoridating agent is dissolved or diluted (such as mixing
tanks) or injected (such as metering pumps). In some situations backflow prevention may be achieved simply
through using an air gap. Any backflow device must comply with the current high hazard device
requirements of AS/NZS3500.
b)
Control equipment
It must be physically impossible for any component of the fluoridation feeding or control equipment to be
manually plugged into standard electrical outlets for continuous operation if isolation of the power supply


  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             18

is used for the stop/start control of the dosing equipment. Any manual mode (or ‘test’) switch for the
fluoridation chemical feeding equipment should not permit permanent selection (such as spring-loaded
switches) and should return to the off position when released to prevent unattended manual operation.
Al  key components of the fluoride dosing control system must be interlocked to ensure total fluoride dosing
system shutdown in the event of failure of any individual equipment item and to ensure that the dosing
system cannot operate unless water is flowing. These key components should include, but are not limited
to:
•
Stop/start/pacing signals;
•
Feeders;
•
Metering pumps;
•
Solution transfer pumps;
•
Solution tank levels or weight;
•
Dilution water pumps; and
•
An online monitoring system.
Refer to Section 4.4 for the key overdosing controls.
An assessment of the possible causes of overdosing must be conducted during plant design and, where
appropriate, interlocks and alarms designed into the system to prevent overdosing of fluoride.
d)
Corrosion and dust suppression
Corrosion prevention measures should be implemented for all fluoridation plants.
Dust control measures should be implemented where sodium fluoride and sodium fluorosilicate are the
agents used.
These measures wil  help protect the equipment, the operational staf  and the neighbours surrounding the
plant.
Fluorosilicic acid bulk and day tanks should be ful y sealed, including water traps on overflows, and the
tank headspace vented to outside the building, to minimise corrosion risks.  Ventilation around dosing areas
should be considered to minimise corrosion risks.
4.6  Chemical delivery, handling and storage
The delivery, handling and storage of chemicals must be in accordance with occupational health and safety
and environment protection requirements (including Hazardous  Substances  Regulations) to ensure the
safety of staff, the community, the environment and the drinking-water supply.
4.6.1
Chemical delivery and quality assurance
The drinking-water supplier should ensure that the chemical supplier has a quality assurance system for
the supply and delivery of the fluoridating agent to ensure its chemical purity, safe delivery and use. The


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link to page 19 link to page 22
quality assurance system should be implemented to manage all the factors associated with the
specification, contract management, supply (including transportation), purity, storage, use and handling of
fluoride compounds that could adversely impact upon the health and safety of staff, contractors and
consumers. This quality assurance system should be included as part of the Drinking Water Safety Plan.
4.6.2
Bulk chemical storage
The drinking-water supplier should ensure that there is sufficient chemical available and readily accessible
to ensure continuity of water fluoridation. The drinking-water supplier should document its' assessment of
storage requirements (taking into consideration availability of the fluoridating agent, transport, procurement
strategies and itinerant populations).   Design guidance is provided in Volume 2.
4.6.3
Bag loaders/Vacuum Loading Systems
Where a dry fluoridating agent is used, the design of the plant should minimise airborne dust and the need
for manual handling. Where manual handling is necessary, it should be in accordance with the Code of
Practice for Manual Handling and the Health and Safety at Work 2014.
4.7  Chemical mixing, dosing and analysis
4.7.1
Mixers
Fluoride solutions should be homogeneous, irrespective of preparation method.  Mechanical mixers should
be used for the preparation of sodium fluorosilicate solutions.
4.7.2
Softeners
If using sodium fluoride, the fluoridation plant should include a water softener where the total hardness of
the water used for dissolving sodium fluoride chemical exceeds 75 mg/L as calcium carbonate.   This
requirement applies only to the water used to make up the fluoride solution in the mixing tanks and not to
the main water supply being treated.
4.7.3
Dry feeder systems
Dry feeder systems must meet the fol owing requirements:
•  Ensure accurate delivery of the required volume or weight of fluoridation chemical for the quantity
of water being treated and must be sized for the maximum flow of the treatment plant.
•  The dry feeder, tank solution level, mixer, and metering pump must be control ed to meet the
functionality requirements of Section 4.5.
•  Include a dust extraction system to meet the requirements of Section 4.6.3.
4.7.4
Injection point
The location and detailing of the chemical injection point must:
a)
Provide homogenous mixing (minimum coefficient of variance of 0.05) of the chemical in the treated
water (where necessary mixing devices should be used) before the first take of  or sampling point


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b)
Minimise loss of fluoride by precipitation with other chemicals (such as those containing calcium,
aluminium and magnesium) or treatment processes (such as coagulation, filtration and pH correction), by
dosing the fluoride fol owing filtration and as far away as practicable after final pH correction if using lime
c)
Minimise the possibility of siphonage and overfeeding
d)
Include provision of a sampling point fol owing mixing
e)
Be located upstream of buffer storage of treated water
f)
Not allow any bypass or secondary pipework (or channel) into which the fluoride chemical wil  not
be dosed (except for fire-fighting purposes or other non-potable water).
g)
Consider the impact of any recycle flow streams to avoid "double dosing".
4.7.5
Flow measurement
A flow meter must be provided to measure and communicate the water flow, and to pace the fluoride dosing
equipment over the full water flow rate range. The metered flow must be truly representative of the flow
into which the fluoride is dosed.
The flow rate signal must be fed back from the meter to the fluoride dosing system to enable automatic
adjustment of the fluoride dose rate. Use of electromagnetic flow meter or similar with an accuracy of ± 1
per cent over the complete range of flow is recommended. The accuracy must not exceed ± 3 per cent. The
flow meter must  be installed in accordance with the manufacturer's recommendations (particularly in
relation to the length of straight pipe upstream and downstream of the meter).
4.7.6
Fluoride Sampling and Analysis
An online fluoride ion analyser is used after the dosing point to measure the concentration of fluoride in the
final treated water. The sample point supplying an analyser (or a grab sampling tap) must be located such
that the measurement reflects the real-time dosing performance of the fluoridation plant. To achieve this
requirement:
•
The sampling point must be located such that adequate mixing has taken place before the
sampling point.
•
The time taken for the sample to travel from the sampling point to the instrument should be kept to
a minimum.  The sampling point must be before the first draw of  for a consumer (or plant service water
offtake), and should be located upstream of the treated water storage.  Where chlorine contact is separate
to treated water storage, the sampling point may be after chlorine contact, prior to treated water storage.
The sole purpose of the online fluoride ion analyser is to provide an independent check of the quantity of
fluoride that has been added to the drinking water flow. It must not be used to provide feedback for trimming
the fluoride chemical dose rate.
The fluoride ion analyser should use the ion-selective electrode (ISE) analysis method or an alternative
method that has been proven to be just as accurate. Accuracy to at least ± 0.15 mg/L should be achieved
by a properly calibrated and well-maintained instrument in a production environment.


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Interferences in the measurement using ion selective electrodes should be considered.  Interferences are
typically not an issue if the water has:
•
Consistently low aluminium and iron levels (i.e. consistently below 0.1 mg/L for aluminium and 0.2
mg/L for iron), and
•
A relatively stable pH that is between 5.5 and 8.5.
If the water to be sampled falls outside this range a Total Ionic Strength Adjustment Buffer (TISAB) should
be used, with the instrument able to alarm on exhaustion of the buffer.
Al  ISE analyses, including online ISE analyses, should be performed at a constant temperature, or results
corrected for temperature, as ISE measurements are water temperature dependent.
Grab samples should be taken at a frequency that accords with the instrument manufacturer's instructions
(but at least monthly) to check the calibration of the on-line analyser. The samples should be analysed
using a bench-top analyser (the ISE method, SPADNS method, the ion chromatography method, or other
validated test method can be used for this purpose), and the results compared with those from the online
analyser to ensure the accuracy of the online analyser.  Periodic (at least quarterly) checks against an IANZ
accredited analysis shall be completed.
4.7.7
Control and alarms
The fluoridation plant must generate alarms and respond to the fluoride action limits as specified in Table
2.
Al  dosing systems must be configured so as to be ‘fail safe’, that is, failure of a critical component
automatically leads to the cessation of dosing and generation of an alarm. If it is not possible for the unit to
fail safe, the PLC must be configured to ensure that fluoride wil  not be added to the water supply if a failure
occurs.  Software interlocks are acceptable.   Loss of sample water to the online fluoride analyser must also
generate an alarm.
All alarms, including fluoride concentration alarms, where online instrumentation is installed must inform a
resource capable of immediate response even after hours. Where dosing is stopped during automatic
operation that is outside of the normal operating parameters of the plant (either manually or by shutdown
alarms), dosing must not restart automatical y without manual on-site intervention.
Where automatic shutdown systems can be manually overridden (such as for maintenance purposes) any
override events must be logged and the override facility configured such that the operator is aware that an
override is activated (such as by the activation of a local or telemetry alarm).
The operation of shutdown systems must be ful y tested at least annually and the outcome of these tests
recorded. The testing procedure must be developed as part of the risk management planning as described
in Section 3.2.
4.7.8
Plant security
The drinking-water supplier should control access to the fluoridation plant to prevent unauthorised access
which wil  minimise the risk of anyone being injured. Appropriate signage must be provided to indicate the


  WATER NEW ZEALAND | Good Practice Guideline for the Fluoridation of Water Supplies             22

presence of the fluoridating agent,  any required personal protective clothing or equipment, and that
authorised entry only is permitted.
Access to the fluoridation plant should be restricted to authorised personnel through provision of a security
locking system.



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5  Operation and Maintenance
Al  plant and equipment used for adding fluoride to a drinking-water supply needs to operate in a safe,
reliable and precise manner. This requires the  drinking-water supplier to  ensure that the plant and
equipment is well maintained.
5.1
Operational monitoring and verification monitoring
5.1.1
Monitoring of fluoride concentration in the raw water
The fluoride ion  concentration in the raw water should be analysed at least annually, but preferably
biannually in summer and in winter. Prior to design, more frequent monitoring is suggested. The sample
must be analysed for fluoride ion concentration at an IANZ accredited laboratory. The raw water fluoride
ion concentration must be taken into account when designing and operating the fluoridation plant.
Should significant variation in natural fluoride ions be found, this needs to be taken into account in the
dosing system operation, which may require a fluoride analyser prior to fluoride dosing to inform the
operator of the correct fluoride dose.
5.1.2
Quantity of fluoride dosed
Every 24 hours the mass of fluoride consumed by the plant (determined from the gross quantity of chemical
used) must be calculated and divided by the volume of water that has passed the fluoride dosing point. This
is another check of the average concentration dosed over each 24-hour period. Any inconsistencies must
be investigated and remedial actions taken to bring the actual dose within the operating dose range (refer
to Section 4.3).
5.1.3
Monitoring of the treated water
Monitoring of the treated water shall comply as a minimum with the Quality Assurance Rules requirements.
Requirements of this Guide should also be complied with. The sampling programme must be integrated
into the Drinking Water Safety Plan.
The drinking-water supplier must have a procedure to investigate and rectify 0.15 mg/L or more
discrepancies between the monitoring results and the fluoride concentration as determined from the
quantity of fluoride dosed and the independent checks required by the Safeguards (Section 4.4).
5.2  Quality assurance
The quality assurance system must ensure the fluoridation process is adequately monitored and
maintained such that any discrepancy, equipment reliability issue or unacceptable variability in the final
fluoride concentration is readily identified and ef ectively rectified.
The drinking-water supplier must also include the details of the quality assurance (QA) and quality control
(QC) framework that wil  be implemented to verify the accuracy of the fluoride  testing results, and the
corrective actions and process by which operators wil  be informed in the event the fluoride dosing system
is either under dosing or overdosing.


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The QC framework must comprise activities (checks) designed to ensure:
•
data integrity (consistency and accuracy)
•
use of standardised procedures for sampling, analysis and data interpretation
•
identification of errors or omissions, and estimation of uncertainties
•
calibration of equipment
•
credible results that relate to the data and analysis.
The drinking-water supplier must ensure that the Operations & Maintenance Manual (described in Section
6.3) is a control ed document with defined procedures/processes for amendment.
5.3  Maintenance and calibration
The drinking-water supplier should carry out monthly plant inspections at a minimum and record in writing
the outcome of the inspections and any resultant actions. In some instances, the HAZOP may determine
that a more rigorous plant inspection regime is required. Plant inspections wil  help ensure effective process
control, determine whether equipment is operating normally and identify the need for maintenance.
Al  equipment and instruments considered vital for process control should be maintained and calibrated
regularly according to maintenance and calibration schedules documented or referenced to in the
Operation & Maintenance Manual (see Section 6.3). Performance of metering pumps should be calibrated
at least monthly by measuring the volume of solution pumped during a measured time interval.
Drinking-water suppliers  should have evidence of maintenance and calibration of all plant items and
equipment to provide Taumata Arowai on request.
5.4  Operational personnel
The drinking-water supplier must ensure that operational personnel (employees or contractors) are
appropriately skil ed and trained in the management and operation of the fluoridation plant, and that these
competencies are maintained (and that this is documented in the Water Safety Plan). Operational personnel
must have an adequate knowledge of the principles of fluoridation (including the risks), the type of plant or
equipment and its operation and maintenance.
A National Certificate in Water Treatment (Site Operator) - Level 4 (or equivalent), or preferably a National
Diploma in Drinking Water - Water Treatment (Site Technician) - Level 5 (or equivalent) is recommended as
a minimum qualification for operators of fluoridation plants.
Operational personnel must have a sound knowledge base from which to make effective operational
decisions. This requires training in the methods and skil s required to perform tasks efficiently and
competently. Operational personnel should be aware of the potential consequences of system failures, and
how decisions made can affect the safety of the scheme.



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5.5  Occupational health and safety
In the area of safety, and the handling and storage of dangerous goods, the Health and Safety at Work Act
2015, Hazardous Substance and New Organisms Act 1996 and associated regulations have precedence
over this Code. If clarification is required in these areas,  then WorkSafe New Zealand wil  provide the
defining interpretation.
The health and safety measures discussed below provide a basis for a drinking-water supplier to assess
the control measures it should employ to manage occupational and safety risks associated with fluoridation
systems. The control measures listed are not exhaustive and the use of these control measures (set out
below) in no way ensures that compliance with the above mentioned Acts and Regulations is achieved.
Health and safety measures for consideration in the design and operation of a fluoridation plant include:
a)
Safety in Design to ensure a safe working environment and facilitate safe working practices
b)
Effective control measures are applied to mitigate risks as identified by the risk assessment
c)
Adequate training for plant operators about the specific hazards associated with the fluoridating
agent
d)
Accessibility of the Material Safety Data Sheet (MSDS) for the fluoride chemical by maintaining the
current MSDS in the Operation & Maintenance Manual, and providing a copy close to where the substance
is used to enable reference to it by operators who handle the substance
e)
Pipework and tanks used for storage and distribution of fluoride chemicals comply with the relevant
standards and are appropriately distinguishable (for example, colour coded and labelled) from other plant
pipework
f)  The installation and arrangement of the equipment to ensure that the handling and operation of the
equipment meet workplace health and safety requirements
h)
Electrical control panels for the fluoridation plant are protected and should be located outside the
fluoridation room
i)
The atmosphere of any areas where fluoridating agents are stored or used is safe for workers, and
ventilation and dust extraction as appropriate is provided for the selected chemical
j)
Appropriate personal protective equipment and hand washing facilities are supplied and
maintained by the drinking-water supplier at the fluoridation plant for mandatory operator use
k)
Emergency eyewash/showers are available where fluoridating agents are stored and handled
l)
Emergency skin treatment such as calcium gluconate gel or similar.
5.6  Environmental safety
The drinking-water supplier should ensure that the operation of the fluoridation plant does not result in
environmental harm.


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In its management of the fluoridation plant and ancil ary equipment and activities, the drinking-water
supplier must consider the Resource Management Act 1991 and relevant regional or unitary plans.
5.6.1
Spills and leaks
The drinking-water supplier must ensure the fluoridation plant and equipment is operated to minimise the
risk of fluoridating agent spil s or leaks. Any spil s or leaks must be contained and must not come into
contact with or be stored with incompatible chemicals.
Where fluorosilicic acid is used then appropriately sized bunding with chemical resistant lining and other
measures (such as drip trays) must be provided to contain any spil age. The design of bunding must facilitate
the safe removal of any spil age, and be consistent with the Code of Practice HSNOCOP 47 Secondary
Containment Systems and other relevant New Zealand standards. In designing the fluoridation plant, the
inclusion of all components containing fluorosilicic acid (including the chemical feeding equipment) in the
storage bund area should be considered as an effective way of reducing environmental risks.
Operating procedures must include measures for managing spil s and leaks of the fluoridating agent,
including in-built detection devices, surveil ance, corrective actions and remedial works, and notification
and reporting to the appropriate authorities. Fluoride piping should be visible so that it can be easily
inspected for integrity. Where pipes are not visible, leak detection measures should be in place.
5.6.2
Release to the atmosphere
Where dry fluoridating agents are used, measures must be implemented to control dust. This includes
designing the plant to prevent the escape of powder into the fluoridation room and atmospheric discharges.
Dry sweeping of dry fluoride chemical should not occur. If powder is spilt, then it should be cleaned by
vacuuming that is fitted with a HEPA filter to prevent dust. Operators must use personal protective
equipment, and this should be dictated in the Operation and Maintenance Manual.
5.6.3
Waste disposal
The management or the disposal of waste containing fluoride must be in accordance with the Hazardous
Substance Regulations. Wastes include fluoride chemical and plant and equipment that have been in direct
contact with fluoride chemical.
The drinking-water supplier must document and implement an environmental waste disposal plan for
fluoridating agent spil s and leaks, contaminated fluoridating agent and fluoridating agent containers.



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6  Documentation
6.1
Design report
Water suppliers should document the design of new and upgrading of existing fluoridation facilities in a
Design Report, which should include:
•
The name of the drinking-water supply proposed to be supplied, including the Taumata Arowai
identification numbers
•
Plans including:
-  General description of facility and process including an outline of the overall treatment process,
description of fluoridation facility, and the design capacity of the plant, expected minimum and
maximum flows in normal operations and the expected growth of flows with time.
-  Process and instrumentation diagrams showing al  key items by appropriate symbol.
-  A site  plan, and a ‘general arrangement’ showing the fluoridation facility in the context of the
overall treatment plant.
-  Evidence of the chemical selection process, natural fluoride content, optimum fluoride level and
the dosage concentration.
-  Fluoride design control limits, maximum pumping rate, feed rate and dosage calculations.
-  Functionality of the fluoridation plant including details of intended process control, process and
instrumentation (including process and instrumentation design), control philosophy for the
proposed facility and integration into overall treatment process.
-  Risk assessment as per Sections 3, 4.1, and 4.5.1, including the supply and delivery risks, storage
risks and the prevention or control of dosing risks associated with human error, plant malfunction
and plant performance.
-  Supplier of the selected fluoridating agent and that supply is complying with the Maximum
Al owable Values outlined in Volume 2, Appendix A.
-  Plans showing the spatial relationship (including levels) between the storage and metering facility
and the dosing point, the relationship between the dosing points for fluoride and for any other
chemicals added ‘post treatment’, and the pipeline layout from the dosing point downstream to
the next component in the plant such as the clear water storage
-  Measurement of fluoride ion concentration in the treated water, monitoring programme and quality
assurance
•
Commissioning plan.
Documentation of the fluoridation plant design should be incorporated in the drinking-water supplier’s
Drinking Water Safety Plan. Plant operational staff must be sufficiently trained so that they have knowledge
of the location of these documents and are familiar with their content before commissioning. Operators that
were absent from this training should be trained once the plant has been commissioned.



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6.2   Completion of work
Upon completion of plant construction and commissioning, the drinking-water supplier should maintain the
fol owing documentation:
•
Operation & Maintenance Manual (refer section 6.3)
•
Emergency Management Plan (refer section 6.4)
•
Commissioning records verifying that the fluoridation plant installation is in accordance with the
plans and specifications and its operation is safe and reliable.
6.3  Operation & Maintenance Manual
The Operation & Maintenance Manual must contain sufficient information to facilitate the operation and
maintenance of the fluoridation plant by the operational staf . At minimum it must include:
•
Standard operating procedures for the plant
•
Maintenance and calibration schedules for items of equipment and instrumentation
•
As-constructed drawings, equipment manuals, and functional description
The Operation & Maintenance Manual should be a control ed document which must be integrated into the
drinking-water supplier’s quality management system.
6.4   Emergency Management Plan
The drinking-water supplier must develop and implement an Emergency Management Plan to manage
incidents and emergencies, including fluoride overdosing, spil s entering the environment and operator
exposure.
The Emergency Management Plan must address how the system wil  be managed to prevent any duration
of fluoride concentrations over 1.5 mg/L (the MAV) reaching consumers.
An Emergency Management Plan must address:
•
Procedures for shutting down the equipment in the event of overdosing
•
The actions required to identify and rectify the problem
•
Action required to advise and protect the public in the event of a significant overdosing event
•
Reporting protocols including a clear chain of command and designated responsibility.
The Emergency Management Plan must be integrated into the Drinking Water Safety Plan or reference
within it.



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link to page 23
6.5  Record keeping
The drinking-water supplier should keep records verifying that the fluoride plant is managed and operated
in accordance with this Guide, with the Drinking Water Standards and the Quality Assurance Rules. The
records must be maintained and made available for inspection upon request by Taumata Arowai. Records
include:
•
Regular chemical analysis of fluoridating agent delivered
•
Regular analysis of concentration of fluoride in raw water
•
Plant and equipment calibration certifications and maintenance data
•
Routine testing of critical alarms and corrective actions and outcomes of the system shutdown tests
•
Surveil ance monitoring and audits records
•
Staff training records.
The drinking-water supplier must, at a minimum, also record the fol owing parameters at the frequencies
indicated:
a)
Continuously (minimum 5 minute interval records) as/where required by the Drinking Water Quality
Assurance Rules
•
Water flow
•
Online fluoride concentration (where monitored)
•
Fluoride solution flow (where monitored)
b)
Daily
•
The volume of water treated
•
The quantity of fluoride added to the water (based on day tank or hopper and dose flow meter,
where monitored)
•
The stock of fluoride on hand
•
The results of fluoride analysis of the samples of water taken from the treated water at the intervals
required – on site and IANZ accredited samples
•
Average fluoride concentration each day on the basis of the online analyser records (where
monitored)
•
Average fluoride concentration each day on the basis of the loss of mass or volume in the dosing
tank (if using day tank)
•
A reconciliation of each of the independent checks (refer Safeguard D and Section 4.7.6)


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7  Reporting and Auditing
7.1
Annual reporting
Reporting of compliance with the Taumata Arowai Quality Assurance Rules is required.
For supplies providing water to populations greater than 500 people fluoride levels in water leaving a
treatment plant must be continuously monitored. The rules that relate to continuous monitoring in the
Drinking Water Quality Assurance Rules must be complied with. These water suppliers must report annually
to Taumata Arowai the number of days in each year that fluoride levels in water leaving a treatment plant
complied with the MAV set for fluoride in the Drinking Water Standards.
For supplies providing water to between 101 and 500 people, Taumata Arowai requires that fluoride levels
in water leaving a treatment plant must be analysed twice weekly.  These water suppliers must report
annually to Taumata Arowai the number of weeks in each year that fluoride levels in water leaving a
treatment plan complied with the MAV set for fluoride in the Drinking Water Standards. The Taumata Arowai
fluoride analysis requirements for these supplies, are lower than those specified in this Good Practice Guide
which specifies on line analysis.
The Ministry of Health may require further reporting on minimum fluoride levels and wil  advise water
suppliers of these requirements.
7.2  Notification requirements
Taumata Arowai must be notified of emergency and exceptional situations as described below  under
Emergency and Exceptional Notifications.
Fluoride concentration in drinking-water supplied in a water sampling locality exceeds or may exceed
1.5 mg/L.
Notify Taumata Arowai Immediately, investigate the cause of the exceedance and take appropriate action.
Fluoride concentration measured at the fluoridation plant that exceeds 1.5 mg/L, however, does not
enter the drinking-water supply.

This does not require a mandatory notification,  but  Taumata Arowai should be notified. In addition, an
internal investigation into the cause of the incident should be carried out and action should be undertaken
and documented.
Fluoride concentration in drinking-water supplied is less than 0.6 mg/l  for a continuous period of >72
hours.
This does not require a mandatory notification, but Taumata Arowai should be notified.
If the rolling annual average fluoride concentration of drinking-water in a water supply has exceeded,
or is expected to exceed, 1.0 mg/L in each quarterly compliance period.
Taumata Arowai should be notified.


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Bibliography
Taumata Arowai, 2022, Drinking Water Quality Assurance Rules, Wel ington, New Zealand. Available at:
https://www.taumataarowai.govt.nz/assets/Uploads/Rulesandstandards/DrinkingWaterQualityAssuranceRules
2022Released25July2022.pdf
American Water Works Association, Sodium fluoride standard (ANSI/AWWA B701-18). AWWA, Denver.
American Water Works Association, Sodium fluorosilicate standard (ANSI/AWWA B70218). AWWA, Denver.
American Water Works Association, Fluorosilicic acid (ANSI/AWWA B703-19). AWWA, Denver.
American Water Works Association, Water Fluoridation principles and practices, Manual of water supply practices
(6th edition). AWWA, Denver.
Code of Practice HSNOCOP 47 Secondary Containment Systems, 2012. Environmental Protection Authority. New
Zealand. Available at:
https://www.worksafe.govt.nz/assets/dmsassets/2/2269WKS1hazardoussubstancesACOPSecondary
containmentsystems.pdf
Standard methods for the examination of water and wastewater (24th Edition) 2012. Published by American Public
Health Association, American Water Works Association and Water Environment Federation, Washington.

Further information
Manatū Hauora information on fluoride:www.fluoridefacts.govt.nz
New Zealand Dental Association www.nzda.org.nz
National Fluoridation Information Service www.rph.org.nz



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