A water firm’s plans to bring universal metering to all Sussex customers could hit the counties’ poorest homes.

Southern Water’s proposals to introduce 100% metering has already been approved by Government body Defra.

They claim the scheme will reduce water consumption by 10% and save the average customer more than £70 off their annual bill.

But consumer groups have said they fear metering will be installed before a water poverty policy is in place - leaving households whose benefits do not cover the cost of water hundreds of pounds out of pocket.

Meyrick Gough, water planning and strategy manager for Southern Water, which provides water services to about 400,000 homes across Sussex, said the introduction of household meters was necessary to combat waste.

He claimed that Sussex’s large population, coupled with warmer and drier years caused by climate change, meant it was necessary to protect the vital resource.

Mr Gough, who said poorer households will need to be “helped” with meter payments, said 75% of the counties’ customers had supported full metering during public consultation.

He said: "We do recognise that there will be winners and losers in the whole of this process.

"Meters show an overall reduction in consumption. That's based on hard evidence that we have. But we do recognise that there will be certain groups which we will have to help."

The firm said the average bill for an un-metered customer was £399 per year, compared with £325 for those with a meter.

But Dr David Bland, the Consumer Council for Water's regional chairman, said the consumer group was concerned that water meters would be installed before any water poverty policy was developed.

He said: "Electricity and gas are covered for poor people under the benefit system.

"Water is not, so a change in the price of water goes directly against the incomes of these people without any mitigation."

But he added: "The fairest system is water metering so that everybody knows what they're using and chooses to use it but that those who are not very well off are assisted in paying for it."

Tony Greenstein, secretary of the Brighton and Hove Unemployed Workers’ Centre added: “I’m absolutely opposed to enforcing water meters on people who don’t want them.

“The problem is that large families will use much more water and if they are on low incomes they are going to find it difficult to pay.

“Water is a basic utility and it should never have been privatised to begin with.”

Lewes MP Norman Baker said: “This will obviously be an unwelcome move for some people but it is a necessary move towards making people value an increasingly scarce resource.

“We have in some parts of the area less water per head than the Sudan. You would not expect to pay an annual fee for electricity no matter how much you use and water should be no different.

“I support the measure but there need to be safeguards for people with particular health problems or low incomes.”

Currently under the Watersure scheme, water companies have to offer help to customers on low incomes who have three or more children or if someone living in the house has to use more water because of a medical condition.

If accepted on the scheme customers' annual bills will be a maximum of the average bill for households in their area.

Southern Water supplies water to about one million customers and treats and recycles waste water from about two million households in Sussex, Kent, Hampshire and the Isle of Wight.

About 25% of homes across the country have water meters fitted.

Ofwat, who will rule on the plan in the autumn, will also set funding for the metering scheme, which will determine how the programme is rolled out.