Kawerau District Council
REPORT ON DRINKING WATER QUALITY PERFORMANCE
1 JULY 2024 – 30 JUNE 2025
Kawerau District Council – Report on Drinking Water Quality Performance for 2024-2025
EXECUTIVE SUMMARY
An independent assessment of performance against the Drinking Water Quality Assurance Rules 2022
(Revised 2024) (DWQAR) and Water Services (Drinking Water Standards for New Zealand) Regulations
2022 (DWS) has been completed for Kawerau District Council (KDC) as a “water supplier” for the
period 1 July 2024 – 30 June 2025 (assessment period). This report supports KDC in verifying its
performance against statutory drinking water quality requirements.
The assessment included the review of performance for the Kawerau Water Supply consisting of one
treatment plant and two distribution zones.
The assessment was undertaken by Wai Comply Limited (Wai Comply) and uses the bacterial and
protozoal modules or equivalent of the DWQAR to form the scope of the audit. The rules selected
(rule sets) from within the modules al ow the audit to; verify the infrastructure relevant to the rule is
in place, determine the operational performance of the barrier(s), and check whether a specific or
associated monitoring requirement is met.
This report details KDC’s rule set performance for the WTP and zones with the outcomes listed in the
DWQAR Performance Assessment Summary table directly below. A brief description is included where
any outcome is listed as “Not met”. Additional y, any exceedances of a DWS Maximum Acceptable
Value (MAV) during the assessment period for the E. coli determinand has been reported separately
in the DWS MAV Summary table below.
The annual assessment outcomes contained in this report were drawn from periodic assessment
statements referred to in the Assessment Results section of this report.
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Kawerau District Council – Report on Drinking Water Quality Performance for 2024-2025
DWQAR PERFORMANCE ASSESSMENT SUMMARY
A summary of performance for the supplies assessed is included in the table below.
Water Supply Component
Rule Module
Rule Set(s)
Outcome
Kawerau
Kawerau WTP
T3 Bacterial
General Monitoring
Met
UV Disinfection
Not met
T3 Protozoal
General Monitoring
Met
Protozoal Rules, UV Disinfection
Not met
Kawerau Zone D3
Residual Disinfection
Met
Microbiological
Met
Upper Val ey
D3
Residual Disinfection
Met
Zone
Microbiological
Met
The fol owing tables provide summarised information relating to findings where the Rule Module or
Rule Set(s) were assessed as ‘Not met’. The specific rules associated with the non-performance are
reported within the respective statements for the period.
Kawerau Water Supply
On 01/10/2025, the requirement for UVT in water flowing through the UV reactors to meet or exceed 91.2%
for at least 95% of the day was not met.
On 18/02/2025, the requirement for flow through the UV reactors to not exceed 362.5 m3/hr for at least 95%
of the day was not met. This was due to four newly commissioned pumps al running simultaneously, rather
than a maximum of two-pumps running at a time. KDC commented that these UV flow rate exceedances were
not reflective of normal operations and that the pump setup has since been altered to a two-pump
configuration. KDC also noted that the fol ow up E. coli samples were al within the acceptable range, and
KDC did not believe a public health risk occurred due to the nature of the event, and the causes behind it.
DWS MAV SUMMARY
The DWS MAV table below summarises any instances where the E. coli determinand was exceeded in
any drinking water samples col ected from KDC water supplies during the assessment period:
Determinand (MAV)
Supply Component
Outcome
E. coli (<1/100 mL)
Al KDC WTPs and zones assessed
MAV limit(s) not exceeded
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Kawerau District Council – Report on Drinking Water Quality Performance for 2024-2025
INTRODUCTION
This ‘Report on Drinking Water Quality Performance’ has been developed using information
specifical y provided by KDC that does or does not demonstrate performance with the DWQAR or DWS
for the period 1 July 2024 – 30 June 2025. The fol owing sources of information provided the basis for
the audit:
Responses to an Initial Request for Information.
Continuous monitoring monthly reports and supporting data for the WTP.
Raw SCADA data for the WTP.
Spreadsheet monitoring results for zones.
This ‘Report’ on drinking water performance does not take into account any specific DWQAR or DWS
performance that occurred prior to, or fol owing, the dates defined within the assessment period
unless considered material to the overal outcome.
RESPONSIBILITIES OF THE WATER SUPPLIER FOR THE AUDITED INFORMATION
The water supplier is entirely responsible for meeting al necessary legislative requirements that apply
to it. The water supplier is responsible for both preparing, and providing the information audited
ensuring that such information is free from material misstatement. The water supplier is also
responsible for disclosing, as applicable, any matters which may inhibit the ability to reasonably make
a determination as to whether performance has been achieved. The water supplier is responsible in
ful for the outcomes of the audit, as the responsibility for achieving compliance with any applicable
legislation sits solely with the water supplier.
AUDITING ORGANISATION, AUDITOR INDEPENDENCE & PROFESSIONAL PRACTICE
Wai Comply is a drinking water compliance advisory company which was set up in 2017 to service the
drinking water industry. Wai Comply employs specialist audit, assessment and inspection personnel
who hold extensive knowledge and expertise in drinking water supply operation, and regulatory audit
practices, with a proven record of utilising international auditing (inspection body) practices.
An independent assessment of performance against the DWQAR and DWS has been completed for
KDC as a “water supplier” for the period 1 July 2024 – 30 June 2025 (assessment period). This report
supports KDC in verifying its performance against statutory drinking water quality requirements.
Wai Comply has been contracted to provide an independent assessment of performance against the
DWQAR and DWS for KDC as a “water supplier” The decisions detailed in this report and the
performance statements are based on Wai Comply’s methodology below. The Wai Comply personnel
performing the assessment have no perceived or actual conflicts of interest pertaining to a
relationship with, or interests in the supplier or its subsidiaries and control ed entities, other than
being contracted to perform this assessment.
METHODOLOGY
The assessment of performance was undertaken by the audit team who performed a variety of audit
approaches which included;
Requests for information including the water supply, WTP and zones KDC is responsible for and
the respective DWQAR modules and rule sets, and
Remotely based documentation reviews (i.e., desktop assessments of performance
reports/statements), and
Direct communication with KDC, seeking clarification and guidance on matters defined within the
performance documents/reports.
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FINDINGS
The fol owing finding types are used in the report for performance against the DWQAR:
Met: Result where the performance requirements applicable to the WTP or Zone were achieved.
Met*: Result where the initial assessment of requirements applicable to the WTP or Zone
indicated performance were not achieved, however after additional technical information and
circumstances were assessed, the finding was qualified as met. This finding and associated detail
is included in the Assessment Result section but is omitted from executive summaries.
Not met: Result where the performance requirements applicable to the WTP or Zone were not
considered to be met.
Any exceedances of a DWS MAV for applicable determinands has been reported separately, including
the component name (WTP or zone), date of sample and laboratory result.
DWQAR SCOPE
The audit scope and methodology applied by Wai Comply is intended to provide KDC with an
independent assessment of performance against the DWQAR performance and DWS. The
assessment(s) conducted used the bacterial and protozoal modules or equivalent of the DWQAR to
form the scope of the audit.
The rules selected (rule sets) from within the modules al ow the audit to; verify the infrastructure
relevant to the rule is in place, determine the operational performance of the barrier(s), and check
whether a specific or associated monitoring requirement is met. The table below lists the DWQAR
Module, rule sets and the rules included in the scope of the audit.
Rule Module(s) Rule set
Rules in audit scope
T3 Bacterial
General Monitoring
G13, G14, G17
UV Disinfection (Bacterial)
T3.15 (excluding sensor checks, monitoring locations by
exception), T3.16, T3.17, T3.18, T3.19, T3.20, T3.21
T3 Protozoal
General Monitoring
G13, G14, G17
Protozoal Rules
S3.1, S3.2, T3.22
UV Disinfection (Protozoal) T3.85, T3.86, T3.87, T3.88, T3.89, T3.90, T3.91 (excluding
sensor checks, monitoring locations by exception)
D3
Residual Disinfection
D3.19, D3.20
Microbiological
D3.29
DWS SCOPE
The DWS specify the MAVs that relate to parameters applicable to drinking water. Demonstrating
achievement with the DWQAR are a means for which a supplier can ensure that the provision of
drinking water does not exceed the MAV for determinands listed in the DWS. The primary
determinand relevant to the DWQAR assessment is E. coli as health risks arising from microbial
contaminants can lead to rapid and major outbreaks of il ness.
WATER SUPPLIES AND ELECTIONS
In order to ensure an accurate assessment, the audit team engaged with KDC across the audit period
to confirm the water supplies, WTPs and zones KDC is responsible for and the respective DWQAR
modules and rule sets. The table below provides a summary of this information, which was confirmed
by KDC and used to guide the assessment against the DWQAR for the period from 1 July 2024 to 30
June 2025:
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Kawerau District Council – Report on Drinking Water Quality Performance for 2024-2025
Water Supply Component
Rule Module
Rule Set
(population)
Kawerau
Kawerau WTP
T3 Bacterial
General Monitoring
UV Disinfection
T3 Protozoal
General Monitoring
Protozoal Rules, UV Disinfection
Kawerau Zone
D3
Residual Disinfection
(6921)
Microbiological
Upper Val ey Zone
D3
Residual Disinfection
(800)
Microbiological
ASSESSMENT RESULTS
The audit team has performed an assessment for the period 1 July 2024 – 30 June 2025 based on the
water supplies, DWQAR modules and rule sets outlined in the preceding section of this report. The
results of the assessment are set out in the DWQAR Performance Assessment Summary section above
with specific detail communicated in the referenced documents below:
Kawerau District Council – Statement on Drinking Water Quality Performance – July to December
2024, sent via email to KDC on 19/06/2025.
Kawerau District Council – Statement on Drinking Water Quality Performance – January to June
2025, sent via email to KDC on 26/09/2025.
The referenced performance statements outline the findings of the assessment but also includes
observations supporting the findings and where appropriate, recommendations for consideration.
RECOMMENDATIONS
Recommendations were made as part of the audit, and these have been included in the individual
performance statements. A summary of the significant recommendations identified throughout the
assessments has been included below:
Continue to work towards updating the reporting to align the performance summaries to reflect
DWQAR requirements. Specifical y regarding T3.89, consideration should be made to altering
the UVT percentage calculations to ensure the number of non-compliant minutes is compared
to the total minutes the UV reactor(s) produced water each day in line with Taumata Arowai’s
rule clarifications.
EXCLUSIONS
Wai Comply were engaged by KDC to conduct an independent assessment of performance against the
DWQAR and DWS. The methodology with which the audit was applied, including defined ‘exclusions’
were detailed and agreed with the acceptance of the contract proposal. As such, al proposed
‘exclusions’ were considered to be accepted by KDC.
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REPORT RELEASE
The audit findings and report were authorised for release on: 26 September 2025
Michael Walker – Lead Auditor
Technical Assessor
Wai Comply Limited
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