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Water treatment

Our new water services regulator, Taumata Arowai is currently consulting on new Drinking Water Standards, Drinking Water Quality Assurance Rules, Drinking Water Acceptable Solutions and Aesthetic Values. Submissions are open from 17 January to 28 March 2022, visit Taumata Arowai - Citizen Space to have your say.

How do we treat your water?

Our treatment plants take raw untreated water, sourced from the district’s bores, springs, streams and the Waikato River and remove contaminants including suspended solids, bacteria, algae, minerals and pollutants. The end result is treated (potable) drinking water, which is safe to drink. Waikato district's water comes from a variety of sources and so a range of water treatment processes are used at individual plants. Each treatment plant is designed to deal with the characteristics of the source of supply. 

We ensure compliance with the Drinking Water Standards of New Zealand (DWSNZ 2005) revised (2018). 

Flushing your water pipes

The drinking water standards require all councils to advise on flushing water pipes which haven't been used for more than half a day. This is because water settles in household and other buildings' pipes overnight or during long gaps between tap use, along with any metal particles from the pipes themselves plumbosolvency.  

That's why it's a good habit to get into to run the tap for a few seconds first before filling a cup, glass or other container with water for drinking or cooking food. 

Plumbosolvent Water

Plumbosolvent water is water that can dissolve metals in fixtures and fittings. If left undisturbed for several hours in a pipe or on a metal surface, the water will absorb small amounts of dissolved metals which can then be delivered via the tap to your glass, cup or kettle. The amount of metal which will dissolve from a fitting depends on how 'plumbosolvent' the water is; temperature; the composition of fittings used for the plumbing set up; and the length of contact time between the static water within the pipe.

In New Zealand, the heavy metals that dissolve in drinking water from plumbing fittings are lead, nickel, cadmium, copper and antimony. 

All water is plumbosolvent to some extent, but soft, slightly acidic water dissolves metals most readily.


Fluoride is added to council water supplies in Ngaruawahia, Huntly, Te Kauwhata, Southern Districts, Pokeno and Tuakau. No fluoride is added to water supplies at Raglan, Te Akau, Onewhero and Port Waikato. 

Fluoridating Raglan Drinking Water Supply

The Ministry of Health and Taumata Arowai (as the new economic regulator) are implementing the fluoridation of drinking water for water supplies that service over 500 people under the (Fluoridation of Drinking Water) Amendment Act 2021.

Across the Waikato District, our larger schemes already provide fluoridated drinking water, and we have received notification from the Ministry of Health that the Raglan supply will be issued directions for fluoridation in the near future.

Fluoridating water greatly reduces rates of preventable tooth decay and is a proven public health measure to improve overall oral health.

The below letter outlines the next steps from the Ministry of Health Director General for Waikato District Council and other Territorial Authorities who will be required to implement fluoridation.

Flow Restrictors

Many in our district will have a flow restrictor placed within their meter, this limits the amount of water that passes through the trickle feed system to 1.8m3 a day, 1.3 liters a minute. 

Customers can request to have the flow restrictors removed from their water supply for up to four months. The flow restrictor is removed to supply full flow water while a storage tank and pump equipment is installed on the property, usually during a building project.  

Water Quality

Yellow to rusty brown water, stains on washing or stale taste.  Rusting iron pipes at home or sediment in the water supply.  Turn a cold tap on full for 20 minutes. If the water turns clear, the brown colour is probably due to rusting iron pipes at home. 
If the water doesn't clear or it still tastes stale after turning the tap on full, the problem is not in your pipes. Small particles settle at some places in the water system. Dirty water results if this sediment is disturbed in some way. Contact us to request a flush of the supply mains - call our freephone 0800 492 452. 
Metallic taste or smell  Corroding pipes or fitting (plumbosolvency).  Turn a tap on full for a couple of minutes to flush the pipework - particularly if it is being used for drinking or cooking. 
Green or blue water, green stains on plumbing.  Corroding copper pipes at home.  Turn a tap on full for a couple of minutes to flush the pipework - particularly if it is being used for drinking or cooking. 
White, cloudy or milky water.  Air in the water.      
If you hold up a glass up to the light, there will be tiny bubbles moving up from the bottom of the glass. This is not harmful. 
We can flush the mains to get rid of the air if the problem continues - call us on our freephone 0800 452 492 to discuss this if you need to. 
Slight smell of chlorine.  Chlorine in the water. Council adds chlorine to disinfect the water. This is not harmful, and the smell will not continue for long.