Drinking Water Sampling
Data Guidelines
Acknowledgements
This document is an initiative of the Water New Zealand, Smart Water Infrastructure Group. Contributors to the document were:
Abi Croutear-Foy, Aquawach
Andy Gaul, Connexis
Dave Pinkney, Christchurch City Council
Dave Wyllie, Tonkin & Taylor
Mark Homenuke - WaterOutlook
Michael Howden - Stantec
Nicolette Voskuilen, ProjectMax
Quentin Griffiths – Lutra Limited
Rob Deacon - Eurofins Food and Water Testing NZ
Robyn Abernethy – Watercare Laboratory Services
Sundra Tatiparthi - Pattle Delamore Partners (PDP)
Feedback and review has been provided by Noah Hensley – Taumata Arowai
Copyright © 2024 Water New Zealand
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Disclaimer
Water New Zealand and individual contributors make no representations, and give no warranties of any kind, whether expressed or implied, concerning the information contained in this document. The document and all information contained in it are provided "as is", and are subject to change without notice. Any risk arising out of its use remains with the recipient. Water New Zealand and individual contributors are not responsible for the results of any actions taken on the basis of information in this guideline, or any loss, damage, costs, or expenses of any kind which may arise in any way out of, or result from, any use of material or information in this guideline.
Publisher
Water New Zealand | PO Box 1316, Wellington 6140 | P: +64 4 472 8925 | E:enquiries@waternz.org.nz | W: www.waternz.org.nz
ISBN 978-1-0670357-1-6
Introduction
Water suppliers are responsible for regularly sampling our drinking water to make sure it is safe to drink. Through sampling we collect data to show there are no harmful contaminants in our drinking water, or prompt immediate remedial action if issues are found, this protects safety of water, giving effect to Te Mana o te Wai.
Drinking water sampling involves different people from different organisations, from the sampler who collects the water sample, the laboratory who tests the sample, the water supplier who must review the samples and take immediate action if the drinking water is unsafe and Taumata Arowai, the water services regulator, who sets the minimum requirements for sampling in the Drinking Water Quality Assurance Rules (the Rules). The Rule Summary List summarises sampling and reporting requirements for different determinands over different supply populations.
These guidelines describe the roles and responsibilities and what data they need to collect and share to help anyone involved in drinking water sampling and give confidence in the laboratory test results.
These guidelines include:
• A description of the roles and responsibilities for the water supplier, sampler, laboratory and regulator (Taumata Arowai)
• A data dictionary recommending minimum requirements for the data that needs to be collected and shared. These data requirements could form the basis for contracting sampler and laboratory services and designing data management tools and software.
• Appendices sharing considerations for sampling procedures, sampling programmes, sampling p oints and sampling requirements for small supplies
• A glossary of terms and resources
Although there may be some principles in common, these guidelines do not focus on sampling from continuous monitoring equipment.
A sample is just that: A tiny proportion of total water volume passing by a specific location at a specific time. Sampling and test results provide critical verification, but on their own they do not guarantee of drinking water safety. Good water safety planning and risk management are also needed to assure that dynamic drinking water systems are producing safe drinking water.
Good Data Management Practices
Good data management practices mean that we can access, understand and trust the drinking water sample data.
Trust
There are multiple ways we gain trust in drinking water sample data. Ensuring that there is a documented Chain of Custody which can be used to trace and verify who handled the sample and data about it.
Data such as the sample site details, equipment calibration, testing methods, and collection times help to build trust relating to the reported results. This will also help people to understand where there may be limitations with the data.
Determinands and Units
Care should be taken to record the specific determinand and unit of measurement:
• Different units affect the value, e.g. mg/mL (milligrams per millilitre) is 1000x mg/L (milligrams per litre) or mg/L NO3 (nitrate) is 4.43 x mg/L NO3-N (nitratenitrogen).
• Different units may have subtle differences, e.g. for E. coli (Escherichia coli) CFU/100 mL (colony forming units per 100 mL) can be correlated, but not directly comparable to MPN/100 mL (most probable number per 100 mL), where the different units reflect different test methods for E. coli .
Software
Using software is essential for the good management of drinking water sampling data. Laboratories should use a Laboratory Information Management System (LIMS) to record their data. Water Suppliers may choose to use compliance management software such as Infrastructure Data or WaterOutlook to collect, manage, review and report on their drinking water sampling data, especially for councils or large supplies. Taumata Arowai provides the self-service portal, Hinekōrako, for water suppliers and laboratories to notify adverse test results and report on compliance with the Rules as well as maintaining Registers of Drinking Water Supplies and Accredited Laboratories.
Both Infrastructure Data and WaterOutlook can automatically integrate with LIMS and Hinekōrako, eliminating manual data entry effort and errors.
Contracts / Employs
Water Supplier
Contracts Services
Sample + Data
Data (Reporting )
Data
Data (Notifications )
Sampler Laboratory Regulator (Taumata
Arowai)
Water Supplier
Water suppliers, including councils, council-controlled organisations, central government, schools, and private and community supplies, have the overall responsibility for providing safe drinking water meets regulatory standards. This involves protecting their drinking water sources and managing their treatment plants and distribution systems.
For drinking water sampling, water suppliers need to:
1. Employ or contract trained samplers to collect drinking water samples
2. Contract laboratories to test samples.
3. Develop and follow a sampling programme defining what determinands will be sampled and how frequently in accordance with requirements in the Rules (See Appendix 1 and 4).
4. Maintain sampling points: construct and maintain secure, accessible sampling point (see Appendix 3)
5. If sampling discovers that drinking water may be unsafe, for example, the Maximum Acceptable Value (MAV) for a determinand is exceeded, the supplier must take immediate action to protect public health, n otify Taumata Arowai, investigate and rectify the problem and advise consumers (WSA s21(2)).
6. Regularly report d rinking water sampling data to Taumata Arowai in accordance with the Rules.
7. Educate the public about the safety of their drinking water, how this is maintained, monitored and publish data to support this.
Sampler
The sampler collects water from sampling points throughout a drinking water supply. Samplers may be employed or contracted by the water supplier or laboratory. They need to be suitably trained and qualified in the collection of samples.
For drinking water sampling, samplers need to:
1. Plan an efficient route to ensure timely delivery to the lab.
1. Follow a Standard Operating Procedure (SOP) specified by either the drinking water supplier or from laboratory, e.g. AS/NZS 5667.7:1998. Good procedures prevent cross-contamination and ensure accurate and representative results (see Appendix 2).
2. Collect a water sample in a container labelled with the Sample ID and according to a schedule set out in a sampling programme from the water supplier
3. Complete any field readings required using a handheld meter (e.g. temperature, pH, free available chlorine) (See Appendix 2).
4. Collect any data required for and fill out the Sample Submission Form supplied by the testing laboratory (recommended fields covered in Drinking Water Sample Data Dictionary).
5. Deliver samples to the lab oratory along with all required data, ensuring samples are kept within the temperature required by the SOP (e.g. 0-10oC for E. coli).
Laboratory
Laboratories use a range of sophisticated equipment and methods to test the levels of different determinands in drinking water samples that cannot be tested in the field.
Laboratories must be accredited by IANZ to test drinking water samples. A Register of Accredited Laboratories is published online.
For drinking water samples, laboratories need to:
1. Receive drinking water samples and required data from the sampler or courier and store the samples according to their SOP
2. Verify the sample has been collected, stored and transported correctly, based on the data from the sampler. Otherwise, it may not be possible to provide accurate test results.
3. Test the drinking water sample according to the sampling programme. Review, validate and collect the required data, including testing methods, determinands tested, and correct units.
4. Share required data with the drinking water supplier.
5. If the test result found in a drinking water sample exceeds the Maximum Acceptable Value (MAV) the laboratory must notify the water supplier and Taumata Arowai as soon as practicable (Water Services Act s73(2)).
Regulator (Taumata Arowai)
Taumata Arowai regulates drinking water suppliers to ensure they are providing safe drinking water. They set the Maximum Acceptable Values (MAV) for determinands in the Drinking Water Standards and the Rules.
For drinking water sampling, the regulator:
1. Provides oversight that water suppliers are taking appropriate steps if the Drinking Water Standards are not met.
2. Analyses drinking water sample data from water suppliers across Aotearoa to identify trends and extract insights.
3. Publishes trends and insights in the annual Drinking Water Regulation Report and, ideally in future, data for researchers and the public.
4. Shares sample data from drinking water sources with Regional Council and when requested by persons via the Official Information Act.
5. Takes action such as educational activities, creating guidance materials, monitoring suppliers’ activities, issuing directions, investigating serious incidents or accepting enforceable undertakings to ensure water suppliers provide safe drinking water.
Suppliers can find more information here: Monitoring water quality | Taumata Arowai and Water services insights and performance | Taumata Arowai.
Drinking Water Sample Data Dictionary
Sample ID String (From the Sampler) 12-ABC- 1, A unique identifier for the sampler.
Lab Sample ID String (From the Lab) 2024-06-14-120
Water Supplier List (Drinking Water Register) Hurunui District Council
Supply ID List (Drinking Water Register) AMB001
Supply Name List (Drinking Water Register) Amberley
Supply Component ID List (Drinking Water Register) AMB001LE
Supply Component Name List (Drinking Water Register) Leithfield
Sample Site ID List (List from Water Service Provider)
A unique identifier for the sample assigned by the laboratory which can be used throughout the process.
Statutory responsibility for the supply of safe drinking water
A unique identifier for the supply from the Public Register of Drinking Water Supplies
The common name of the supply from the Public Register of Drinking Water Supplies
A unique identifier for the supply component (source, plant or zone) from the Public Register of Drinking Water Supplies
The common name for the supply component (source, plant or zone) from the Public Register of Drinking Water Supplies
Point 1 A supplier’s internal identifier for a specific sample site (tap) Sample Site Coordinates Lat/Lon (WGS84) -43.190675, 172.737854
and longitude of the sample site
Sample Site Address Text 17 Leithfield Road Street address closest to the sample site
Determinand List (From:DWQARparameter_determinand)
coli, turbidity, FAC, pH A constituent or property of water that can be determined or estimated in any given sample
Can provide context for anomalous test results, e.g. a fault reagent batch.
Field Reading Determinand List (From:DWQARparameter_determinand) FAC A constituent or property of water that can be determined or estimated in any given sample
Field Reading Value Number
Field Reading Unit Text oC
Measurement of a determinand that is captured at the same time and location that the sample is taken
Identifies the units of measurement for a field reading Meter ID Text
Field
Meter Make Text Hach
Meter Model Text FAC Analyser 2000
Meter Calibration Date Date/Time (Recommend: YYYY-mm-ddTHH:MM:SSZ)
Meter Calibration Person Text
2024-02-10 10:40
Calibration Tech 01
Meter Calibration Reading Number 7
Notes Text “Good Sample”
Sampling SOP Text "AS/NZS 5667.7:1998"
Sampler ID Text Sampler-01
Sample Date/Time Date/Time (Recommend: YYYY-mm-ddTHH:MM:SSZ)
2024-06-10 09:08
The manufacturer of the field reading instrument
The device model of the field reading instrument
Demonstrates how recently the instrument was calibrated to ensure accurate measurement
Traces the performance of the last calibration back to the individual responsible for it
Documented result of the calibration procedure
An optional set of notes associated with the sample
The name of the Standard Operating Procedure (SOP) followed during the sampling
A unique identifier for the person who took the sample.
The time and date the sample was obtained. Water
Temperature of water when sample taken Weather Conditions During Sample Text Wind / Rain / Snow
Lab Arrival Date/Time Date/Time (Recommend: YYYY-mm-ddTHH:MM:SSZ)
Water Temp. at Lab Number
2024-06-10 14:10
This may provide context to anomalous test results.
Provides assurance of the Chain of Custody and that the sample is handled according to requirements.
Temperature of sample when received by lab
Test Anomalies String Not in the right container Anything worth mentioning
Test Method String COLILERT18H
Units List mg/L
Test Result Value Number <1
Exceeds MAV Boolean Yes
The accredited test method the laboratory uses to determine the test result.
The unit of the sample value
Does this sample exceed the MAV) for the determinand in the Drinking Water Standards of New Zealand.
Appendix 1 – Sampling Programme Considerations
When designing a sampling programme, you must consider the minimum monitoring requirements for a supply’s population in the Rules. The sampling programme should ensure that the following requirements are met for the applicable rule module. Additional monitoring requirements identified in a drinking water safety plan or source water risk management plan. Other requirements to include in a sampling programme include, but are not limited, to:
• Locations to be sampled from.
• Determinands to be sampled for.
• Sampling schedule
• How the schedule will be adjusted for increased compliance requirements when test results exceed 50% and 100% of the MAV.
Samples must arrive at a testing laboratory within the test holding time. Delays in transit due to weather or other events may impact the number of samples that can be used in compliance reporting. Therefore, suppliers could consider adding contingency samples to a sampling program, to ensure that the minimum requirements will still be met.
Appendix 2: Sample Procedure Considerations
Taking and delivering the sample to the laboratory contains some risk for contamination, especially for drinking water samples taken for bacteriological monitoring. To minimise this, samplers should follow a strict sampling routine to make sure the quality of the sample is not compromised. Use the sample containers provided by your laboratory. Sample procedures for samples taken at the treatment facility or distribution network will be similar while source water samples might not have a tap which can be sterilised. Sampling procedures vary according to the determinand being sampled for.
Sterilise sample point:
• Good practice is to flame the outlet on tap, which can be done only if the tap is approved to be flamed. Use a portable burner to heat metal tap to the point where surface bubbles start steaming (at least 15 seconds). DON’T touch tap since it will be very hot!
• Where it is unsafe or unsuitable to flame, use alcohol wipes and methyl alcohol (meths). Clean tap inside and out. Spray meths on it and wait for 20 seconds.
• Do not sterilise taps prior to obtaining samples for chemical testing, particularly metals, as flaming a tap can result in metals leaching out of taps into the sample
• When taking samples for both chemical and bacteriological samples, take the chemical samples first according to appropriate procedure, then sterilise the tap and take bacteriological samples.
• If your sample point doesn’t have a stainless steel or copper (metal) tap which can be flamed off, try and install one. (see Appendix 3)
• Hands must be sterilised with alcohol hand wash, prior to sample collection. S terile/medical gloves may be worn and should always be worn for chemical sampling
Flush Sampling Tap
• Flush for a minimum of 2 minutes, or for the time identified for each sample point.
• Flushing removes s tagnant water. The time to achieve this can vary. A standard flush is 2 minutes, but this should be confirmed for each sample point by flushing until chlorine readings and/or temperature stabilise.
• If water is visibly turbid, continue flushing until water runs clear.
• Once the sample point is flushed, undertake any field readings. These may include free available chlorine (FAC), pH and temperature.
• When undertaking field readings, do not immerse the meter probe (e.g. temperature, pH) in your sample container - use a separate container or measure from the flow.
Microbiological Testing:
• After effective flushing reduce flow and ensure a smooth flow coming from the tap
• Rub an alcohol wipe around your hands, the outside of the bottle including the lid to sterilise then allow dry.
• Open the bottle and take the sample sheltering from the elements e.g. rain, heavy wind. Don’t place the lid anywhere while taking the sample-in one hand should be the sample bottle and the other hand the lid-this will prevent hand contact on the interior of the sample bottle.
• Fill the bottle slowly up to a minimum of 100mL. If the sample is less than 100mL it cannot be tested.
• Tighten the lid and invert to mix the dechlorinating agent if used and supplied by laboratory (if the dechlorinating agent is washed out by accident the sample must be discarded).
Chemistry Testing:
• It is not necessary to sterilise the sampling point for chemistry testing
• Ensure you fill each container provided by the laboratory – depending on the testing required, you may need to collect several different containers
• Containers may contain preservative - do not rinse bottles, or fill to overflowing, as you may remove the preservative
• Some containers may need to be filled with no headspace available –contact your testing laboratory if unsure.
Sample label and transportation:
• Label the container(s) with the sample point name, date and time of collection (for registered water suppliers please include your Supply ID)
• Complete sample submission form provided by the laboratory. Sample date and time must also be noted on this form and all other fields completed. If you are requesting microbiological testing, the field temperature must also be supplied.
• On return to the vehicle, place the microbiology sample directly into a dedicated, clean chilly bin with frozen ice packs 12/24V Chilly bins are preferred.
• Drinking water samples for Chemistry and Microbiology testing can be stored in the same chilly bin but it is strongly advised to use different bins.
• If you are sampling for wastewater and drinking water you MUST use 2 different chilly bins for transportation to minimise the risk of cross contamination.
• Samples must be received at the laboratory and tested within 24 hours of sample collection. Samples must arrive at a temperature less than the temperature taken at the time of sampling (and not frozen) – if not they are non-compliant samples
• Label these chilly bins as “Drinking Water Microbiology Only” and use them ONLY for Microbiology tests.
• You must keep wastewater and other environmental samples away from drinking water samples.
Deliver samples to laboratory within right timeframe
• Samples must be tested within 24 hours of been taken in the field. Plan your sample routine well (traffic congestion can make a sample invalid) and confirm with laboratory.
• Plan for possible contingency-if the sample has to be discarded based on e.g. temperature too high, time elapsed, a second sample needs to be taken and processed almost immediately to avoid non- compliance.
Appendix 3: Sampling Points Considerations
Sampling points need to be of standard design so the sampler can easily follow a best practice sampling routine. They should have their unique identifier clearly displayed on them and using QR codes could be helpful. Sample points should be:
• Lockable (if in a public space)
• Easy to access, including good and safe car parking
• A stainless steel sampling tap that can be flamed
• Well maintained – cleaned regularly, no overhanging greenery
• Close to watermains and should not require much flushing (if part of a bigger reticulation system).
Here are two examples:
Glossary
Chain of Custody
Coliforms
Determinand
Drinking Water Quality Assurance Rules
E. coli
Free available chlorine (FAC)
A record of who has handled the water sample, and how to provide assurance in the data.
Group of bacteria which lives in the intestinal tracts of warm-blooded animals and used as indicator for faecal contamination.
A constituent or property of water that can be determined or estimated in any given sample.
Rules set out by Taumata Arowai to define minimum compliance requirements to ensure safe drinking water (link).
Escherichia coli , used as an indicator organism, may indicate faecal contamination in drinking water. May cause gastroenteritis.
Free available chlorine - if chlorine is used for disinfection a level of 0.2 mg/L must be achieved in the distribution system.
Hinekōrako Is the self-service portal for drinking water suppliers, IANZ accredited drinking water testing laboratories and wastewater network operators.
Laboratory For drinking water testing the laboratory needs to be accredited and using accredited testing methods.
MAV
Maximum Acceptable Value.
Sampling Programme Set up by drinking water supplier to verify their drinking water is safe.
Sample Submission Form
Records the Chain of Custody, records sample information required by the laboratory and lists the tests to be performed. Recommended fields are highlighted in Drinking Water Sample Data Dictionary Example https://www.hilllabs.co.nz/media/wtlbmbon/44956v10_analysis-requestform-onions-nz-pesticide-residue.pdf
