Hamilton's sole water treatment plant was first opened in 1971, and is responsible for the treatment of all of Hamilton's drinking water, which comes from the Waikato River.
The plant is upgraded accordingly to population growth in Hamilton, and while never reaching maximum capacity, in recent days it has been close.

So how does Hamilton water get treated to produce over 2500 glasses to 50,000 Hamilton homes? The first step of Hamilton's water treatment is collecting the water from the Waikato River. The treatment plant's intake pumps are located opposite the Hamilton Gardens, on the south side of Hamilton.

Large and small pieces of debris are picked up at this stage through coarse grills in the pipes. Narrower screens also remove any leaves, twigs and other small matters.
In times where the river level drops below the intake pumps, the council has a barge ready to be lowered into the river, which connects to the intake pumps and takes water deeper in the river.

After being collected from the river and screened, the water is then lifted through pumps with alum and polymer added to assist in separating microorganisms from the water in sedimentation tanks. The clearer water floats on top of the microorganisms and flows out for further treatment into a sand filtration system.


The water is fed through sand filters, leaving remaining microorganisms trapped on top within the sand. From the sand filters, the water is then lifted via pumps into the granular activated carbon filtration system (GAC). The purpose of the GAC filter is to remove organic chemicals, some which are created by algae and can cause problems such as musty taste and odour. From the GAC filter, the water is then lifted again into a Ultra Violet light screening pipes.

The UV lights are effective in effective in inactivating organisms by penetrating their cells and altering their DNA so they are unable to infect or reproduce. Hamilton's water treatment plant has three of these reactors which work as a secondary barrier against microorganisms.

After the UV light screening, the water then has chlorine added which kills any remaining bacteria, and fluoride in accordance with Ministry of Health Guidelines for dental health. The water then flows through a bulk main that rings the city, the ring transports water to the distribution network and the city's nine reservoirs.

The reservoirs have a total storage capacity of 90 million litres, with the water held for a maximum of 24 hours. From the reservoirs the water flows out to over 50,000 houses in Hamilton.