Winter sprinkler bans could be extended into spring if water usage increased to unacceptable levels, Water Minister Bill Marmion has warned.
Amid pleas by the State Government for people to cut back on their water use this summer, Mr Marmion said that prolonging the ban always remained an option if consumption went "off track".
The comments by Mr Marmion came as Labor said that extending or shifting the ban should be considered to reflect Perth's changing weather patterns.
Shadow water minister Fran Logan said that the Government should look at other ways to conserve drinking supplies apart from "begging" people to limit their use.
He said that reinstating Labor's rebate scheme for water-efficient appliances would be a start. The Government should also consider changing the winter sprinkler ban.
The ban, which was introduced in 2010, only applies in June, July and August, with households able to water their gardens twice a week every other month of the year.
Different rules apply to bore owners, who can water their gardens three times a week outside winter.
Mr Logan said that the climate of Perth and the South West was changing and winter rains were increasingly coming later in September and October.
He said that if Labor was to win at the March election it would consider whether the ban should be pushed back or extended into spring to account for the climatic changes.
Doing so, Mr Logan said, could save billions of litres of water a year from the city's precious drinking supplies.
Mr Marmion said there was no immediate intention to alter the sprinkler ban. This was because there had been a "clear shift" in people choosing not to use their sprinkler systems when it was raining.
However, he said the measure would be left on the table.
"Looking ahead, until there is greater certainty on these later rainfall patterns, and while the community continue to do the right thing by keeping their sprinkler systems switched off when it rains, there are no plans to extend the ban on a permanent basis," Mr Marmion said.