Mr Sullivan has accused the Independent Competition and Regulatory Commission (ICRC) of being ''eccentric and wrong'', ''unjustified'', ''regressive'', ''misleading and misrepresentative'', in its views on water pricing and advocating ''year zero regulation''.

The attack comes as Mr Sullivan has also revealed he feels ''guilty'' that the utility's chairman, John Mackay, is quitting.

''I accept his decision but feel slightly guilty as I think he was trying to protect me a little bit,' Mr Sullivan told ABC Radio on Tuesday.

The ICRC's draft report on water prices released in February called for a $230 drop in annual bills for the average family and for the break-up of the cluster of companies that controls the capital's gas, water and electricity supplies.

Senior commissioner Malcolm Gray also wanted more intense scrutiny of ACTEW's spending on water infrastructure projects like the $409 million Cotter Dam enlargement program.

As it begins the search for a new chairman after Mr Mackay's resignation in the wake of the row over Mr Sullivan's pay deal, the territory-owned corporation opened its submission to the ICRC inquiry on water pricing by lashing out at the regulator.

In a draft determination, the ICRC flagged a 16.9 per cent cut to water charges and 19 per cent reduction in sewerage fees to take effect from July. The combined bill for a typical household would fall by about $4.42 a week.

In its submission, published on Monday, ACTEW calls for a 6 per cent increase, and says the commission's approach would cost the territory's taxpayers hundreds of millions of dollars in lost dividends.

''Under ACTEW's proposal an indicative residential customer using 200kL of water per annum would see a combined water and sewerage bill increase of $108 for the year, which equates to a 6 per cent increase after accounting for inflation,'' Mr Sullivan wrote in his submission.

In its report, the commission criticised as ''imprudent'' $50 million worth of spending by ACTEW on the Murrumbidgee to Cotter pumping augmentation project, the Cotter suction and discharge pipelines and the Uriarra Village sewerage project.

Mr Sullivan shot back, accusing the ICRC of changing its stance on the prudence of capital expenditure.

''When a regulator concludes that spending on the Cotter Dam is efficient and writes and advises that

the government's acceptance of prudence is good, ACTEW does not expect the issue to be raised again, still less in terms suggesting imprudent behaviour,'' Mr Sullivan wrote.

Mr Sullivan, who agreed on Monday to a $140,000 pay cut, was scathing of Commissioner Gray's suggestion that payment for the territory's big water projects be shared by future generations.

''ACTEW's submission sets out clearly that this approach will simply overburden future generations and recommends that it be abandoned,'' Mr Sullivan wrote.

''The ICRC's draft directions in this area are eccentric, wrong and should be reconsidered.''

The ACTEW head went on to accuse the commission of proposing ''intervention and interference'' in its draft report.

''It [the ICRC] has proposed intervention and interference instead of oversight of business operations, re-opened historical events, which had been settled by previous regulatory inquiry, applied arbitrary and harmful expenditure allowances that ignore the advice of its contracted experts and skewed the burden of current costs onto future generations,'' Mr Sullivan wrote.

''It does so by drawing a misleading and misrepresentative picture of current issues and arrangements.''