Hamilton's sole water treatment plant is working close to maximum capacity as the hot weather saw the city last week use the most water ever over three consecutive days.

More than 85 million litres of water was used each day between Tuesday and Thursday.

The treatment plant beside the Waikato River has a peak production capacity of 106 million litres per day, an improvement of 42 million litres from when it first opened, with a peak volume of 64 million litres per day.

Despite still some expansion capability before the plant reaches max capacity, the council is calling on Hamiltonians to be mindful of their water use, with a sprinkler ban looming if usage continues to rise.


Hamilton — which must stay within the limits of the consent it has to take water from the river — moved to water alert level two last week, which means sprinklers and watering systems can only be used on alternate days (even street numbers on even days; odd street numbers on odd days) between 6am-8am and 6pm-8pm. Hand-held hosing can be done any time. An increase to water alert level three will mean a complete ban on sprinklers.

With water use being restricted, and more hot weather still on the cards for Hamilton, commentators on the Hamilton News Facebook page are asking why the Hamilton Gardens are not bound by the same restrictions.

City water manager Maire Porter said the "Hamilton Gardens are not bound by restrictions as they do not use treated water, they have a separate consent to take water directly from the river and use this within the gardens."

And while Hamilton Gardens is not watered by treated water, residents generally use treated drinking water for their gardens.

"In order to provide untreated water for gardening and outdoor water use Hamilton city council would need a separate reticulated network, or an alternative method of transporting untreated water, all of which would come at a cost to ratepayers," Ms Porter said.

Commenters on the Hamilton News Facebook page asked if they could set up their own rain tanks to store water, and while Ms Porter said reusing water is encouraged, there a number of factors needed to be taken into consideration when installing a water system.

"There needs to be suitable storage to avoid stagnation and contaminated water as well as ensuring untreated water cannot be mistaken for drinking water. Rainwater tanks connected to drinking water or stormwater systems will require council consent."

Ms Porter said the council will continue to monitor water usage over the coming weeks.
"Over the weekend water use remained high. There is some rain forecast for Wednesday and Sunday so we will continue to assess the need to move to Alert Level 3 on a day-by-day basis."