Sydney Water has been told to deliver $622 million to NSW treasury coffers, a 75 per cent increase on the dividend predicted last year, and return all profit to the Baird government.

The NSW Opposition has accused the government of using the water utility as a cash cow, to replace the soon-to-be privatised electricity network, and warned of the future impact on household water bills.

Sydney Water has been told to return all its profits to NSW Treasury. Credit:Jupiterimages

"Every time you turn on the tap, Mike Baird is taking his cut. Every time you want to bath the kids, Mike Baird is taking his cut. And every time you want to wash the clothes, Mike Baird is taking his cut," said Labor's water spokesman, Mick Veitch.

On Tuesday, Sydney Water will release its pricing proposal for customers for the next four years, for approval by the pricing regulator.