The Selwyn District Council said water samples indicated there are elevated levels of E.coli in the town supply.
"Residents are reminded please do not consume (the water). If you have an alternative source available please use this," a spokesperson said.
"Urgent supplies of bottled water continue to be available to be collected from the Challenge Springfield and a water tanker will be made available this afternoon, location to be confirmed."
The water supply can continue to be used for domestic purposes but not for oral health, food preparation or washing dishes.
The spokesperson said household dishwashers "generally are safe to use if the water reaches a final rinse temperature of at least 66 deg C, or the dishwater has a sanitizing cycle".
"Otherwise, use disposable plates, cups, and utensils. Sanitise all baby bottles."
E.Coli can cause diarrhea/bloody diarrhea, vomiting and stomach pains and cramps.
To wash dishes by hand:
Wash and rinse the dishes as you normally would using hot water.
In a separate basin, add 1 teaspoon of unscented household liquid bleach for each gallon of warm water.
Soak the rinsed dishes in the water for at least one minute.
Let the dishes air dry completely before using again.
The district council will provide a further update on the water supply later today.
