Ed Miliband has pledged to introduce new social tariffs in the water industry in a bid to drive down living costs.
Speaking in Battersea, Mr Miliband attacked the Government on the issue of the cost of living crisis and vowed to "stand up for markets that work for working people".
Mr Miliband said the water industry should be "scrutinised to make sure it is working properly", during an interview with the Evening Standard last week.
The water industry is the latest sector to be scrutinised by the Labour leader after he promised to freeze gas and electricity bills until 2017 if his party won the next general election.
"Something has gone really wrong" in the UK energy market and Parliament has to "tackle that", the shadow energy secretary told Daybreak.
Labour's Caroline Flint said a 46% drop in the wholesale price which was not passed onto customers when her party were in charge, but warned bills were getting worse under the coalition government.
"Prices are going up three times as fast under this Government than they were under us and we need to tackle that."
Environment Secretary Owen Paterson has told water firms it is "crucial" that water bills are kept affordable for "hardworking people".
Environment Secretary Owen Paterson has called on water companies to "look closely" at whether price increases are necessary and introduce special tariffs for hard-pressed households.
In a letter to suppliers, Mr Paterson said the firms should recognise the financial strain people are under.
The intervention came ahead of an Ofwat ruling expected later this week on an application from Thames Water to increase bills by £29 in 2014-15.
The regulator is expected to reject the application and has questioned the profits being made by firms.
It suggested its next Price Review could ease the upward pressure on bills by up to £750 million after 2015.
The Government said a Daily Telegraph report that thousands of homes would be made to install water meters was untrue.
Defra released the following statement:
Millions of families in Britain could face higher bills under new government plans to install compulsory water meters in homes, the Daily Telegraph has claimed.
The Environment Secretary, Owen Paterson MP, this week approved plans to make water companies across a third of the UK fit meters and bill customers for usage.
Ministers have warned that reservoirs are at risk of running dry due to water shortages.