WELSH Water has sought to allay customers' fears following a nationwide hike in water prices.

It was announced today that average water and sewerage bills in England and Wales would rise by 5.7% from April to an average of £376 per household.

Welsh Water said its customers would see an average rise in their bills of 3.8% - the lowest increase out of all water and sewerage companies in England and Wales.

Managing director Nigel Annett justified the price hike by saying his company was investing £1.4 billion to improve its infrastructure over the five years to 2015.

He said: "We are working to give our customers the best possible value-for-money service, while providing the highest quality tap water, reducing the risk of sewage flooding, and protecting our environment.

"The investment to protect coastal waters and rivers has helped gain Wales a third of the UK's Blue Flag beaches, while our rivers are the best in the UK.’’ The price increase is part of an agreement between water companies across England and Wales and regulator Ofwat.

In 2009, it announced a five-year plan of annual rises from 2010 to 2015 to help fund £22 billion of investments.

Other water companies also have customers in Wales.

Ofwat said Severn Trent bills will rise an average 5%, and Dee Valley 5.4%.

Benedict Fisher, head of communications for Ofwat, said inflation was the main reason behind the changes.

"Water companies are monopolies - water company customers can't shop around for water,’’ he added.

"So our job is to make sure customers are protected and part of that protection is to make sure the prices companies charge is limited.’’ However, the Consumer Council for Water expressed concern that many customers were already struggling to pay their bills.

Chair Dame Yve Buckland said: "We will be working with companies and the regulator throughout the next price review to ensure that future water prices are acceptable and affordable.

"In the current economic climate, many customers are struggling with rising household bills and the level of water debt is growing.

"Companies need to tell their customers very clearly what they are getting for their money and to help customers who are having difficulty paying their bill.’’