WA's sewerage system is at greater risk of blockages and leaks because of budget cuts, the State-owned water utility has warned.
The Water Corporation has told the State Government parts of its business are at an "unacceptably high risk of non-compliance" from an erosion of its capital spending program.
Though the corporation was coy on which areas of the State were likely to be affected or to what extent, a spokeswoman said "wastewater treatment processes" were at an increased risk.
Sewage spills because of broken infrastructure at wastewater treatment plants have led to serious pollution in the Swan River and Cockburn Sound.
The warning comes after the Government shaved $560.8 million from the utility's capital budget between 2009-10 and 2012-13 to help reduce spiralling State debt.
The situation was compounded by the need to bring forward $250 million in spending to meet growth in the Pilbara and the Government's $450 million decision to expand the Binningup desalination plant.
In a submission to the economic regulator, the corporation said the funding shortfall could leave it exposed to legal action and a loss of face in the community.
It said the budget cuts and redirected funding resulted in an "unacceptably high risk of non-compliance in some areas of the business".
"The current level of approved capital is insufficient to fund all (business areas) to an acceptable level, with some being only funded to allow an 'undesirable' rather than acceptable outcome and two are funded with an 'unacceptable' outcome."
The Department of Environment and Conservation, which regulates the corporation's wastewater plants, confirmed any licence breaches could mean prosecutions.
Shadow water minister Fran Logan said the utility's claims were a concern and the Government should stump up extra cash after years of significant cuts.
Water Minister Bill Marmion said he was satisfied the corporation could manage any risks.