What are my Legal Obligations for water tank cleaning in New Zealand?

They are committed to ensuring all communities have access to safe and reliable drinking water every day. Guidance and Resources – Taumata Arowai  

In Section 6 of the Water Services Act, it says “drinking water means water that is used for human consumption, or oral hygiene or preparing food and drink, washing utensils that are used for eating and drinking, or for preparing, serving, or storing food or drink for human consumption.”  

The new Water Services Act 2021 clarifies the definitions of ‘safe’ and ‘potable’ water means:  

1. It is safe to drink 

2. It complies with the Drinking Water Standards for New Zealand 2022. 

Taumata Arowai has introduced various regulations for private water suppliers. In summary, as soon as a water source supplies more than one building to provide potable water, it is a water supply and is subject to some form of regulation. The rule of thumb is that the greater the number of people using the water, (and therefore the number of people at risk should anything go wrong with the supply) the greater the water treatment requirements.

The actual legal obligation to clean your water tank depends on the type of property involved and water use – read on to find out the regulations for your situation.

Private dwelling 

In your own private dwelling, you are responsible for your own water supply and there is no legal obligation to meet any minimum standard of care.  While there is no legal obligation, there is good practice to help protect you and your whanau.  The recommendation to clean water tanks at least every two years is our expert guidance for you and your family.  We also recommend UV + Sediment filtration.  

Landlord – single dwelling 

As a landlord you have a legal responsibility to provide potable water to your tenants. Rainwater is considered potable. However, this does not consider the surfaces the water contacts before being consumed.  

There is case law where landlords have been prosecuted for not providing clean and safe water and were instructed to clean the tank and install filtration. This is an extreme no one would wish to reach. It seems common-sense to follow the good practice of regularly cleaning your water tanks and installing filtration to ensure you are providing safe and clean water to your tenants.  

Landlord – multiple dwellings e.g. larger farms with tenanted houses (including employees) 

If your water source is supplying more than one dwelling then you are likely to be considered a small water supply under the auspices of the water regulator, Taumata Arowai.  

In short, this means you need to develop and implement a water safety management plan complete with pre-tank preventative measures, and regular tank cleaning combined with an appropriate UV filtration system. You need to implement the plan and maintain records to show your compliance. The level of regulation changes depending on the number of people using the supply and water source. Safe H2O would be happy to provide more detailed guidance specific to your circumstances at any time.  

Commercial uses 

If you are using rainfed water for preparing and serving food and beverages, you must ensure your water is always safe. This means meeting food hygiene requirements including developing and implementing a water safety management plan complete with pre-tank preventative measures, and regular tank cleaning combined with an appropriate UV filtration system. You need to implement the plan and maintain records to show your compliance. Again, the Safe H2O team would be happy to provide more detailed guidance specific to your circumstances at any time.  

Schools, Marae, Community Facilities 

As the users of the water at such facilities can be a significant number of people, you are required by the water regulator, Taumata Arowai, to develop and implement a water safety management plan and implement measures to ensure clean and safe water for all users.  

This will include pre-tank preventative measures, and regular tank cleaning combined with a validated UV filtration system.  

You need to implement the plan and maintain records to show your compliance. Safe H2O would be happy to provide more detailed guidance specific to your circumstances at any time.

Taumata Arowai has introduced regulations for private water suppliers. All unregistered private water supplies are required to be registered with Taumata Arowai by November 2025 and be fully compliant by November 2028. Those already registered (prior to 2022) must have submitted their Drinking Water Safety Plan (WSP) by November 2022.

Please contact Hamish at [email protected] if you are interested in more information.