What do the revised Drinking Water Quality Assurance Rules mean for me?

A Very Small Communities (VSC) supply provides water for up to 25 people. These supplies can serve up to 50 people for up to 60 days in a 12-month period to allow for short, seasonal increases in population. 

During a planned event 

Updates to VSC Rules focus on what is required when a supply exceeds its population limit.  

During a planned event when the number of people a VSC supply serves exceeds 50 people, the supply is no longer required to meet General or Temporary Drinking Water Supply Rules. This means VSC suppliers are no longer required to conduct source-water testing or cyanobacteria risk assessments during a planned event. 

Instead, the updated VSC.4 Rule requires the supplier:  

• to ensure drinking water is filtered (e.g. with cartridge filters) and either disinfected with UV light or chlorinated (e.g. with sodium hypochlorite) to provide suppliers more flexibility 
• monitor treated water for E. coli and total coliforms in the week before the event and weekly if the event exceeds one week. 

Guidance is being developed to explain the differences between treatment types and how risk assessments can benefit a supply. 

Unplanned population increase 

A new rule has been introduced (VSC.3) to clarify that a supply needs to follow Level 1 rules for the rest of the calendar year if the population exceeds 25 people for more than 60 days in any 12-month period.  

This new rule provides VSC suppliers flexibility to temporarily increase the number of people they provide water to. 

More flexibility in sampling and sharing test results 

• VSC Rules no longer include a minimum period between sample dates.  
• Suppliers are no longer required to share the results of E. coli and total coliform tests with people that own or live in properties connected to the supply.  
• Suppliers must still notify us if they consider their drinking water is, or may be, unsafe, or if it does not comply with New Zealand’s Drinking Water Standards. 

Guidance for VSC supplies will be provided in 2025. 

Monitoring source water 

For suppliers that follow these rules, there are fewer determinands that must be monitored in each type of source water. These rules no longer require suppliers to monitor for:  

• iron in surface and groundwater  
• benzo[a]pyrene in roof water (this chemical is generally only present where soot from fires or fireplaces may be deposited on roofs). 

However, if either of these determinands poses a risk to a specific supply, the supplier must include risk mitigation measures in its Drinking Water Safety Plan, which may include regular monitoring.  

We’ll provide guidance on monitoring for chemicals in source water in 2025. 

The rules still require suppliers to test: 

• surface and groundwater every three years for arsenic, boron, manganese, and nitrate 
• roof water every three years for cadmium, copper and lead. 

Revised Rule S1.3 now requires suppliers to carry out extra monitoring if:  

• (new requirement) any chemical creates a supply risk, or 
• (unchanged requirement) 50% of the maximum acceptable value (MAV) for a chemical has been exceeded for:  
• surface water and groundwater arsenic, boron, manganese and nitrate 
• roof water cadmium, copper and lead. 

When 50% of the MAV is exceeded for any chemical, suppliers are now required to carry out additional testing at least once a year until three consecutive test results are under 50% of the MAV. This gives suppliers more flexibility to determine how often they test their source water in this situation to best manage risk.  

Revised Rule S1.4 was updated to clarify that source water from different abstraction points must be sampled before mixing.  

Cyanobacteria and cyanotoxins 

Revised Rule S1.5 provides more options for suppliers to use to manage and respond to the risk of cyanotoxins in the source water. If suppliers follow the same practices in line with current rules, they will still be compliant at 1 January 2025.  

Revised Rule S1.6 requires suppliers to now record and investigate consumer complaints related to cyanobacteria (rather than just cyanotoxins). This is because cyanobacteria can impact the taste and smell (aesthetic values) of water without cyanotoxins being present.  

In 2025, we’ll provide guidance on cyanobacteria and cyanotoxin management to support small and medium suppliers. 

Reporting requirements 

Rules that were previously listed as assurance rules have been changed to non-reporting rules to make it clearer that suppliers do not need to report on them. However, suppliers are still required to comply with these rules.  

Clarifications 

Rule T1.1 has had wording refined to make requirements related to testing treated drinking water clearer and easier to follow.  

Revised Rule T1.2 clarifies how long and how often monitoring is required when a supplier has identified a chemical that poses a risk to a supply. This rule now requires three-monthly monitoring of water leaving the treatment plant until there are three consecutive results that are less than 50% of the relevant MAV. This supports consistent practices across the sector.  

Filtration 

Rule T1.3 gives suppliers more flexibility when filtering water. Filtration is still required for all water except groundwater abstracted from a depth greater than 30 metres. However, suppliers can now use a wider range of filters. Filtration systems must still meet some basic requirements as outlined in Rule T1.4.  

In 2025, we’ll provide guidance for supplies that need to be filtered to reduce turbidity (how clear the water is). 

UV (ultraviolet) treatment 

Revised Rule T1.5 consolidates ultraviolet (UV) treatment-related rules and information into one rule, and:   

• confirms that suppliers may use equipment certified to an older standard where that equipment was installed before 1 August 2022 
• makes simpler and clearer how UV disinfection units must be installed, maintained, operated and certified 
• clarifies the level (required dose of 40 mJ/cm2) of UV treatment that is needed to inactivate bacteria and protozoa; this is already required under rules in T1 
• provides additional certification options for ÖNORM M5873 (Osterreichisches Normungsinstitut 2001) (previously allowed only for units installed before 1 January 2020) and DIN 19294-1:2020-08. 

In response to feedback provided during consultation, suppliers can continue to use a calculated dose approach or set-point dose approach.  

In 2025, we’ll provide guidance for small and medium-sized supplies on best practice for operating UV treatment devices.  

Reporting requirements 

Rules that were previously listed as assurance rules have been changed to non-reporting rules to make it clearer that suppliers do not need to report on them. However, suppliers are still required to comply with these rules.  

Monitoring  

Rule D1.1 no longer has the requirement to monitor for determinands identified as posing a risk to the supply in the Drinking Water Safety Plan (as this monitoring is now required instead in T1 Rules). This revised rule:  

• continues to require three-monthly sampling in the distribution for E. coli and total coliforms 
• means monitoring is now required in a distribution zone (rather than distribution system) as a supply may have multiple distribution zones with their own water quality considerations that need to be monitored.  

Backflow 

Revised Rule D1.2 includes strengthened backflow requirements to help protect distribution networks from contamination. 

• Each distribution zone must be assessed for both backflow risk and cross-connections every two years. This is consistent with the previous requirement.  
• Suppliers must now keep a register of all points of supply with a medium or high backflow risk. Guidance on what constitutes a medium or high backflow risk will be provided in 2025. 
• A suitable backflow prevention device is still required for the points of supply identified in the supplier’s register. 
• Testable backflow prevention devices now need to be inspected and tested every two years by a suitably trained and qualified person. Testable backflow prevention devices are not common for small supplies. However, if they are installed, then a supplier needs to make sure the device works. In 2025, guidance will be provided on how to arrange these tests. 
• If a backflow prevention device is found to be faulty, suppliers now need to remediate this as soon as possible. 
• Results from tests of backflow prevention devices must also be retained by the supplier. 

Backflow requirements in Rule D1.2 are listed as a non-reporting rule. This means that reporting is not required for this rule but suppliers are still required to comply. 

Monitoring 

Rule S2.1 still requires suppliers to monitor for the same determinands as previously. (See the rule for list of determinands.)  

Rule S2.1 was revised as follows:  

• we increased the monitoring frequency for arsenic and boron from every three years to annually to bring the monitoring frequency in line with other metals  
• we reduced the frequency of pH (a common measure of acidity), and turbidity testing from every six months to annually to help reduce compliance burden. 

Rule S2.2 removes the requirement to monitor for zinc and benzo[a]pyrene for roof water sources. If there are related supply risks, these must be managed in the Drinking Water Safety Plan for the supply.  

In 2025, we will provide guidance on zinc as there is no MAV for zinc in New Zealand’s Drinking Water Standards. 

Revised Rule S2.3 now requires suppliers to carry out extra monitoring if:  

• (new requirement) any chemical creates a supply risk, or 
• (unchanged requirement) 50% of the MAV for a chemical has been exceeded for:  
• surface water and ground water arsenic, boron, iron, manganese and nitrate 
• roof water cadmium, copper and lead. 

When 50% of the MAV is exceeded for any chemical, suppliers are now required to carry out additional testing at least once a year until three consecutive test results are under 50% of the MAV. This gives suppliers more flexibility to determine how often they test their source water in this situation to best manage risk.  

Rule S2.4 was updated to clarify that source water from different abstraction points must be sampled before mixing.  

Cyanobacteria 

Rules S2.5, S2.6, and S2.7 outline cyanobacteria management requirements and provide a supplier more options to meet their responsibilities. 

• Revised Rule S2.5 has the added category of ‘no’ risk for the presence of cyanobacteria, which is intended for deep groundwater sources. 
• Revised Rule S2.6 provides more options that suppliers can choose to use to manage and respond to the risk of cyanotoxins in the source water. However, if suppliers follow the same practices in line with current rules, they will be compliant at 1 January 2025.  
• Under revised Rule S2.7, suppliers must now record and investigate consumer complaints related to cyanobacteria (rather than just cyanotoxins). This is because cyanobacteria can impact the taste and smell (aesthetic values) of water without cyanotoxins being present. 
• The requirement to develop a cyanobacteria/cyanotoxin response plan has been removed from the rules. However, whenever there is a supply risk, we expect suppliers have will plans in place to manage these, including for cyanobacteria/cyanotoxins. 

In 2025, we’ll provide suppliers with guidance on cyanobacteria and cyanotoxin management to support small and medium-sized suppliers. 

Reporting requirements  

Under the revised rules, there are fewer rules that need to be reported on annually (now limited to Rules S2.5 and S2.7).  

Some rules that were previously listed as assurance rules (S2.4 and S2.6) have been changed to non-reporting rules to make it clearer that suppliers do not need to report on them. However, suppliers are still required to comply with these rules. 

Reporting frequency for monitoring rules remains unchanged. 

The T2 rules have been simplified from 25 rules to 10 but requirements have remained similar. 

• Rule T2.1 still requires E. coli, total coliforms and any chemical used in the treatment process to be monitored monthly.  
• Rule T2.2 requires turbidity, free available chlorine (FAC), pH and fluoride to be monitored eight times per month (previously twice a week).  
• Flow monitoring is no longer required. However, manufacturers’ flow requirements for specific UV units and cartridge filters must still be met. See Rules T2.8 and T2.10 for information. 
• Rule T2.3 requires sampling to be spread evenly across a month, on at least three different days (e.g. Monday, Thursday and Saturday) during the month. This replaces the slightly higher requirement to sample on four different days of the week. 
• Rule T2.4 now requires monitoring for chlorate every three months if using calcium hypochlorite. Monitoring requirements for sodium hypochlorite remain the same. 
• Revised Rule T2.5 clarifies how long monitoring is required when a supplier has identified a chemical that poses a risk to a supply. This rule now requires three-monthly monitoring of water leaving the treatment plant until there are three consecutive results less than 50% of the relevant MAV. This supports consistent practices across the sector. 

Supplies categorised as self-supplied buildings  

Rules for self-supplied buildings have changed. All supplies categorised as self-supplied buildings are no longer required to chlorinate the drinking water they supply. (See section 1.5 of the rules for a definition of self-supplied buildings.)  

As a result, self-supplied buildings also no longer need to monitor for FAC and pH. 

Filtration 

Rule T2.7 gives suppliers more flexibility when filtering water. Filtration is still required for all water, with a new exception of groundwater abstracted from a depth of greater than 30 metres. However, suppliers can now use a wider range of filters. Cartridge filtration systems must still meet some basic requirements as outlined in Rule T2.8.  

In 2025, we’ll provide guidance for supplies that need to be filtered to reduce turbidity (how clear the water is). 

UV (ultraviolet) treatment 

Revised Rule T2.10 consolidates UV treatment-related rules and information into one rule, and:   

• confirms that suppliers may use equipment certified to an older standard where that equipment was installed before 1 August 2022 
• makes simpler and clearer how UV disinfection units must be installed, maintained, operated and certified 
• clarifies the level (required dose of 40 mJ/cm2) of UV treatment that is needed to inactivate bacteria and protozoa; this is already required under rules in T1 
• provides additional certification options for ÖNORM M5873 (Osterreichisches Normungsinstitut 2001) (previously allowed only for units installed before 1 January 2020) and DIN 19294-1:2020-08 
• increases UVT monitoring requirements from every three months to monthly with an option to conduct continuous monitoring to help ensure the equipment is operating effectively and water quality is appropriately managed 
• now enables suppliers to monitor UVI or UV dose either continuously or record it twice-weekly.  

In response to feedback provided during consultation, suppliers can continue to use a calculated dose approach or set-point dose approach.  

In 2025, we’ll provide guidance for small and medium-sized supplies on best practice for operating UV treatment devices. 

Reporting requirements  

Under the revised rules, there are fewer rules that need to be reported on annually (now limited to Rules T2.6 - T2.10).  

A rule previously listed as an assurance rule (T2.3) has been changed to a non-reporting rule to make it clearer that suppliers do not need to report on it. However, suppliers are still required to comply with this rule. 

Reporting frequency for monitoring rules remains unchanged. 

D2 Rules now apply for a distribution zone rather than a distribution system. This helps to ensure all areas of a distribution system are managed consistently.  

Monitoring  

Rule D2.1 removes the requirement to monitor for determinands identified as posing a risk to the supply in the Drinking Water Safety Plan (as this monitoring is now required instead in T2 Rules). This rule continues to require monthly sampling in the distribution for E. coli and total coliforms. 

Revised Rule D2.2 requires FAC to be monitored eight times per month (previously twice a week).  

Revised Rule D2.4 requires FAC sampling to be spread evenly across a month, on different days (e.g. Monday, Thursday and Saturday) of the week. 

D2.5 still requires suppliers to monitor for the same determinands as previously, with the exception of zinc. Zinc monitoring requirements have been removed as zinc is not included in New Zealand’s Drinking Water Standards. These standards set out the maximum amounts of metals and other substances that are acceptable in drinking water from a public health perspective. In 2025, we will provide guidance on zinc and drinking water.  

When 50% of the MAV is exceeded for any chemical, suppliers no longer need to carry out additional monitoring. This gives suppliers more flexibility to determine how often they test their source water to best manage risk.  

Suppliers still need to monitor for E. coli and total coliforms monthly. However, to provide increased flexibility, they no longer need a minimum period between sample dates.  

In 2025, we will provide guidance on sampling. 

Rule D2.6 has been revised to provide additional detail on how to test for metals to ensure accurate test results, e.g. by not flaming the tap before taking a sample. 

Backflow 

Revised Rule D2.8 includes strengthened backflow requirements to help protect distribution networks from contamination. 

• Each distribution zone must be assessed for both backflow risk and cross-connections every year. This is consistent with the previous requirement.  
• Suppliers must now keep a register of all points of supply with a medium or high backflow risk. Guidance on what constitutes a medium or high backflow risk will be provided in 2025. 
• A suitable backflow prevention device is still required for the points of supply identified in the supplier’s register. 
• Testable backflow prevention devices still need to be inspected and tested every year by a suitably trained and qualified person.  
• If a backflow prevention device is found to be faulty, it must still be remediated as soon as possible. 
• Results from tests of backflow prevention devices must also be retained by the supplier for at least three years. 

Reporting requirements 

Under the revised rules, there are fewer rules that need to be reported on annually (now limited to Rules D2.7 and D2.8).  

Rules previously listed as assurance rules (D2.3, D2.4 and D2.6) have been changed to non-reporting rules to make it clearer that suppliers do not need to report on them. However, suppliers are still required to comply with these rules. 

Reporting frequency for monitoring rules remains unchanged. 

Minor adjustments have been made to Varying Population Rules as follows.  

• There is no longer a specified amount of time required between taking samples. 
• For those following Rules VP.1 and VP.2, we have clarified that sampling is only required the week before the population increase if this increase was predicted (e.g. planned events or seasonal population changes). 
• Rule VP.2 clarifies that when the population served by a supply drops below 500, the supply must continue following Rule VP.1 until the population drops below 100 people. 
• Self-supplied buildings no longer need to monitor for FAC and pH. 

Note that the previous Rule VP.3 has been split into two Rules – Rule VP.3 (treatment) and Rule VP.4 (distribution).  

Reporting requirements 

All VP Rules are now non-reporting rules. This means that reporting is not required for these rules. However, suppliers are still required to comply with these rules when they apply.