Thames Water is the only water company to ask for permission to increase customer bills
Ofwat, the water regulator, says it will challenge Thames Water's request to increase customer bills by up to 8% next year.
Thames's proposed increase could add £29 to the average annual household bill, says Ofwat.
The regulator is challenging Thames's claim that bill increases are justified because it is facing rising costs.
Ofwat claims Thames has underspent on sewer and sewage improvement schemes.
Thames is the only water company to have applied to the regulator for a bill increase in advance of the next pricing review.
But Ofwat is examining whether financial gains the company has made elsewhere make such bill rises unnecessary.
Ofwat's chief regulation officer Sonia Brown said: "We have been clear that we would challenge Thames' proposed bill increase. So we are looking to see if there are areas where we can claim money back for customers."
Ofwat says it will publish a draft decision on Thames's request in mid-October.
Source: BBC News - Business http://www.bbc.co.uk/news/business-24077217#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa
