RWE, the German owner of UK water firm Thames Water, has reported a 19% rise in first-half operating profits.
Thames supplies eight million users in London and the South East
Utility giant RWE said that surging power prices had helped it to raise profits to 4.1bn euros ($5.3bn; £2.8bn) during the period.
RWE said talks were continuing about a potential sale of Thames Water, thought to be worth about £7bn, although it gave no details about possible buyers.
In June, Thames Water announced a 31% rise in pre-tax profits to £346.5m.
The UK firm was also found to have missed its target for reducing leakages for the third year in a row.
Although it escaped fines from watchdog Ofwat, instead of having to pay a penalty the company was told to invest an extra £150m over five years to replace ageing pipes.
Thames was expected last year to cut the average amount of water leaking from its pipes each day to 860 million litres, but only managed to reduce it to 894 million.
RWE, which also has interests in gas, electricity and recycling, bought Thames Water for £4.8bn in 2000 but analysts reckon it could now fetch a far higher price.
Thames Water supplies water to eight million people across London and the south of England, and also provides sewage services to 13 million customers.
Any sale of Thames Water is likely to be closely scrutinised by the competition authorities.
RWE said it was on track to sell its UK and North American water operations over the next year although it was also considering a possible flotation of the businesses.
"We are conducting various talks and I can not reveal the names of any potential buyers," said RWE chief executive Harry Roels.