I'm a

Te putu, te tiaki me te arotūruki wai

Water collection, treatment and monitoring

We supply water from a mix of rivers, dams and groundwater. We carefully treat, test and monitor the water to make sure you have a steady supply of safe and clean water for drinking and other uses.

Where does your water come from?

Most of Auckland’s water comes from our dams in the Hūnua and Waitākere ranges, the Waikato River and groundwater. In the week finishing 21 July 2024, the proportion of water taken from each source to supply the metropolitan Auckland area was:

  • Dams = 83.83%
  • Waikato River = 16.17%
  • Groundwater = 0%

Where Auckland’s water comes from depends on water storage levels, forecast rainfall, treatment plant capacity and the cost of pumping water to our reservoirs.

Read about our water supply situation

Pie chart showing where Auckland's water has come from in the past 7 days.

How do we treat your water?

We treat all the water we supply to you to make sure it’s safe to drink. When treating your water, we screen it to remove dirt and debris, filter it to remove smaller particles, and then disinfect it to kill germs.

The exact treatment process depends on where the water comes from, as some sources are cleaner than others. We have 17 treatment plants around Auckland to cover all the water sources and over 9,000kms of pipes to get the water to you.

You can learn more about our treatment processes and living near our treatment plants below.

Treating water from different sources
Treating water from our dams
Treating water from the Waikato River
Living near our water treatment plants
Watercare labs

Monitoring and testing water

Testing is a vital part of ensuring that the drinking water we provide is safe and always meets New Zealand Drinking Water Standards. Our labs continuously monitor the water quality from our treatment plants, and we also carry out location-based testing.

Every day our technicians carry out an average of 250 tests on water samples from points across the network, from collection at the source to coming out of your tap.

During collection, we check water for harmful contaminants, such as algae, faecal coliforms, giardia and cryptosporidium. This testing ensures we take quick and appropriate action if unusual results show up, like restricting use of that source.

We also test the water leaving our water treatment plants to check chemical parameters and look for any signs of micro-organisms in the water. We then monitor the pH, water clarity and residual chlorine.

Keeping you informed about water quality

In the unlikely event that the water we supply becomes unsafe to drink, we or the Medical Officer of Health will alert you immediately, do further testing to identify the cause of the quality issue, and take one of the following actions:

  • Temporarily close the supply
  • Vary the treatment process
  • Isolate affected assets/areas
  • Supply water from other supply points or sources
  • Use a tanker to provide water

If you see any issues with the quality of water we supply, such as a change in clarity, taste or smell, please report a fault. We’ll investigate and, if needed, test your water to find out the cause.

Pressure management

It’s important to make sure the pressure in water pipes across Auckland is suitable for everyday use, as high pressure can burst a pipe or cause a leak.

What are the benefits of pressure management?

  • Water pipes last longer.
  • The water supply is more dependable and there are fewer interruptions.
  • It reduces the need for excavation work to repair broken mains.
Diagram showing how gravity affects water pressure.
How does water pressure management work?
What impacts the pressure in water pipes?

Frequently asked questions about water collection, treatment and monitoring