Sussex householders will receive a boost to their finances with water bosses promising below-inflation rises for every home for each of the next five years.

Southern Water unveiled the plans as part of wide-ranging measures to put more money back in the pockets of its 700,000 customers across Sussex.

From 2015 to 2020, the firm has committed to holding any price increases to 0.6% below the rate of inflation – compared to a typical nine per cent above inflation increase from 2010 to 2015.

On the same day South East Water, which looks after the majority of properties in the east of the county, made a similar promise.

It means customers across Sussex are set for a real-terms reduction in the amount they pay for their water supply.

Matthew Wright, Southern Water’s chief executive, said: “We are confident this is the right plan for our customers.”

Southern Water, whose latest accounts show it made a profit of £331 million in 2012/13 – up from £271.6 million in 2011/12, said its plan will cost £3.2 billion to implement and will support an estimated 6,000 jobs.

Other improvements include improved customer service, a 25 per cent reduction in sewer flooding inside people’s homes and businesses and no “serious pollution” incidents in its area.

To make it work, the firm said it will need to find £200 million from its annual budget.

Most of this would be on reducing its spending with bosses ruling out job losses and redundancies.

Mr Wright said: “As we developed our plan, we were fully aware of the tough economic conditions which are making life difficult for a number of our customers.

“We have worked hard to do all we can to balance the need to deliver the improved services customers want, cater for a growing population in our region, safeguard the environment and make sure everyone can afford their bills.”

South East Water said it planned to invest £475 million over the same period as it looks to hold its average annual household bill to about £200.

Both firms will also introduce a new social tariff from April 2015 to help those in financial hardship.

Hove MP Mike Weatherley said: “At a time when more and more of our incomes are going on household bills, it’s encouraging that Southern Water have committed to a below inflation rises for the next five years.”

Industry watchdog Ofwat will now consider both business plans and make a final decision that will determine future water bills by December 2014.