Australia Weather News

A boil water alert has been issued for Darwin and its surrounding areas due to the flooding of Darwin River Dam.

On Monday residents were urged to reduce their water usage following the stalling of water pumps at the city's main dam.

On Tuesday a boil water alert was issued for "all water dispensed from midday today".

Boil water alerts are also in place for the Northern Territory town of Katherine, as well as Wugularr (Beswick) and Tindal, as the region grapples with the aftermath of a major flood.

What is a boil water alert?

Residents are also being urged to conserve the water supply for essential uses of drinking, cooking and basic hygiene.

NT Health recommends using cooled boiled water or bottled water for:

NT Health recommends boiling water by bringing it to a full rolling boil, until a continuous and rapid stream of air-bubbles is produced in the pan or kettle. 

Why is this happening?

Power and Water Corporation said the issue was caused by flash flooding and a "heavy wet season" that lead to the dam being at more than 110 per cent capacity.

Heavy rainfall on Monday caused flooding of the dam's pump station and associated equipment.

John Pease, the acting chief executive of PWC, said the organisation had engineers "working into the night to look at alternative options" to get the pump station back online.

"The protection systems we had in place worked as expected," Mr Pease said. 

"They shut off the pumps to save damage to the pumps, but that means until the water recedes, the pumps will stay off until we can get an interim solution in place."

Mr Pearse said in the meantime PWC had increased supply from its bore fields in rural areas which delivers water to Darwin and surrounding areas alongside the Darwin River Dam system.

He said for the time being, tap water would be discoloured and at a reduced pressure.

Chief Health Officer Paul Burgess said drinking unboiled water brought health risks that were low, but not zero.

"The things we worry about — it might be contamination from that area in the bore water where there are surrounding properties with septic tanks, E. coli, and also a couple of bugs — those can cause quite a nasty diarrhoea. 

"As water use continues throughout the night, we'll now be seeing the bore water starting to flow through those taps. That's the back-up supply, and that's the supply that we're asking people now to boil before using it at home."

Can I shower or wash my hands? 

Yes.

NT government advice states unboiled tap water can still be used for washing dishes and clothes, bathing and other household tasks — just avoid swallowing the water.

The Australian Drinking Water Guidelines adds that for young children — who are more prone to swallowing bath or shower water — sponge bathing is advised "as a precaution".

Should I buy bottled water?

Bottled water is selling out across the Top End, with shelves of bottled water in Darwin supermarkets bare.

In Katherine, some shops have imposed limits on the amount of water people can buy, but stock has still run out.

Authorities say the reopening of the Stuart Highway should help alleviate supply of bottled water. 

Can I use a water filter or filtration tablets?

Water should be boiled even if you have a home filter or fridge or jug with a filter.

National guidance generally advises that filters should not be relied upon.

NSW Health advice states even in commercial kitchens, water should be boiled before being used for cooking and that any filter used needs to be "certified against an appropriate standard". 

However, NT Health did offer an exception, saying that quick boil water taps installed in office buildings are safe to drink from.

As for filtration tablets — which includes chlorine tablets — the Australian Drinking Water Guidelines recommends using them "if it is not possible to boil water". 

How long will this last?

We don't know.

Mr Pease said residents have not reduced water consumption enough since they were asked to cut back last night.

"Consumption hasn't dropped sufficiently so we've had to implement a new contingency measure," he said.

"This is a very fast moving situation as you can imagine, the contingency measure is to change the direction and reduce the pressure of water that comes through the pipes and ultimately out peoples' taps."

Power and Water said crews were working onsite to restore the pump station, using backup generators.

Chief Health Officer Paul Burgess said he had lived in the NT for 26 years and this was the first time he remembers hearing of a boiled water alert for Darwin.