The average household water and sewerage bill in England and Wales will rise by 5.7 percent in 2012 as water companies gear up to invest as much as 22 billion pounds over the next five years, industry regulator Ofwat said on Tuesday.

The increase, about 20 pounds on average, takes into account a rate of inflation of 5.2 percent, and will mean an average household bill of 376 pounds in 2012/13.

The bill changes for this year will come into effect on April 1 and apply until March 31, 2013.

We understand that any bill rise is unwelcome, particularly in tough economic times, Ofwat Chief Executive Officer Regina Finn said. Inflation feeds through into water bills, and this is driving these rises.

Finn noted that companies are investing 22 billion pounds by 2015, or more than 935 pounds for every property in England and Wales.

Shares in the three listed British water companies Pennon, Severn Trent and United Utilities were up about 0.50 percent by 8:45 a.m. British time on Tuesday.

(Reporting by Adveith Nair; editing by Rhys Jones)