The state government is urging residents in bushfire prone areas to not rely on scheme water supplies if they plan to defend their home in the event of a bushfire.
Residents must ensure they have an independent water supply and a pumping capability in the event of a total loss of power.
During a bushfire heat-damaged infrastructure or a cut to power could result in a loss of scheme water supply.
In addition, high demand for water could also lead to a drop in water pressure and cause water supply tanks to empty quickly.
Water Minister Dave Kelly said the Water Corporation was prepared for the bushfire season, however, could not guarantee scheme water would be maintained during a bushfire.
"If you chose to stay and defend your home on the assumption water will keep coming out of your tap or hose, the consequences could be life threatening," Mr Kelly said.
"Many people do not realise that pipes and other infrastructure such as tanks and pump stations could be damaged well before a bushfire reaches anywhere near your property.
"It is crucial you plan to have your own water supply if you intend to stay and defend your property.
"The scheme water network is designed to provide drinking water to the community, it is not designed for fighting bushfires."
Emergency Services Minister Francis Logan said WA was about to face a period of extreme temperatures and heightened bushfire risk.
"The radiant heat from bushfires can melt hoses and plastic fittings, and be so intense that no amount of water will stop it," Mr Logan said.
"If you have time now, then make sure you have put in place a robust and independent water supply, but that means having at least 20,000 litres and a generator with enough fuel to power a water pump.
"If you haven't done that already, then time is rapidly running out to put appropriate measures in place."
Mr Logan urged all residents in high-risk areas to make a bushfire plan using the DFES website.
To find out how to prepare for a bushfire, including having an independent water supply, visit: http://www.firechat.wa.gov.au