Households are expected to be slugged substantial cost of living increases in the West Australian government's second budget.
Water Minister Dave Kelly has already revealed water charges for the representative household will increase by 5.5 per cent in 2018/19.
Shadow treasurer Dean Nalder told reporters ahead of Thursday's budget the Water Corporation was making tidy profits and was "over-recovering".
Other already-revealed cost of living increases include Emergency Services Levy rises to create a rural fire service.
Metropolitan landowners will pay an additional $28 from July 1 while landowners in the regions will pay between $8 and $17 extra.
Mr Nalder said households were already doing it tough with stagnant wage growth, and pointed to a big rise in applications for the Hardship Utility Grants Scheme last year.
"We think it's inappropriate that the state government at this point in time is putting pressure on the households of Western Australia," he said.
Treasurer Ben Wyatt has already revealed the 2018/19 deficit has narrowed to about $900 million, down from the $915 million forecast in the mid-year budget review.
He also says the state remains on track for a surplus by 2020/21 but it will take a long time to pay off debt, which was forecast in December to peak in 2019/20 at $42.8 billion.