The Water Corporation will cut water pressure to tens of thousands of Perth homes as part of long-awaited efforts to save drinking supplies and stem leaks and burst pipes in its ageing network.

Although details of the plan are still to be fleshed out, the State-owned utility confirmed it was preparing for a rollout of the water- pressure reduction program across the metropolitan area from next year.

The revelation comes more than three years after the Water Corp finished a trial of the measure, which affected thousands of homes in the southern suburbs of Shelley, Rossmoyne and Waterford.

The pilot project, which ran between 2007 and 2009, was considered a success by the corporation after it reduced consumption by up to 11 per cent and "significantly" cut leaks and bursts in the mains network.

However, it is understood the utility is wary of a backlash from a full-scale project after almost half the customers involved in the trial who responded to a questionnaire complained about adverse effects of lower pressure.

Prime among them were claims - disputed by the Water Corporation - that reduced water pressure disrupted, and in some cases ruined, household reticulation systems which are hugely popular and often cost thousands of dollars.

The Water Corporation has long planned to expand the trial in Perth, where water-pressure rates are among the highest in Australia, after a report in 2009 found about 20 billion litres leaked from its pipes a year.

The figure, while lower on a comparative basis with other big water utilities, is equivalent to almost half the annual production of the Kwinana desalination plant - 45 billion litres a year.

In a recent interview, Water Corporation chief operating officer Peter Moore alluded to the trial's expansion but stopped short of detailing which suburbs would be targeted and how much it would cost.

Previously, the State-owned group has suggested about 30 per cent of Perth households would be affected by a wholesale reduction in water pressure because many homes already had rates deemed suitably low.

"We spent most of last year doing investigations as to where it might be most appropriate," Mr Moore said. "I would reiterate when we do these programs, we do a lot of work with the community and make sure the pressure, where it's lowered, is to a degree where everyone in the area gets that minimum pressure."