Water bills have risen more than twice as fast as pay over the past decade in an industry which is now "out of control", a new report has claimed.
A study commissioned by Unison showed that bills had trebled since water privatisation in 1989, well above increases in the rate of inflation.
The research, conducted by the New Policy Institute, also found that water firms were making "huge profits".
Unison called on the Government to launch a "root and branch review" of the industry to make sure it is being run in the public interest.
Dave Prentis, Unison's general secretary said: "This private monopoly is the worst of both worlds. Since privatisation, private equity firms have swooped in to grab a lucrative slice of the water industry pie, but households, taxpayers and employees are losing out.
"The time has come to think again, with all options on the table. We need a root and branch review to make sure the industry is run in the interests of consumers not profits."
Dr Peter Kenway, director of the New Policy Institute, said: "The combination of opaque ownership, steady price rises and growing financial weakness should not be tolerated in an industry like water that is obviously too important to fail.
"Our report shows that the industry in England has big questions to answer about the deal it is offering consumers and taxpayers. It is time the Government starting asking them."
The report said that almost a third of an average household water bill goes on profit, compared with 9% in the energy sector.
Water bills have soared by 64% in the past 10 years compared with 28% for average earnings. The study added there was no competition in the industry.