Ofwat's decision to reject Thames Waters' bid to increase prices by 8% is final, but Thames Water could appeal to the Competition Commission.
The company said: "We will review the decision carefully before deciding on our next steps."
More top news
A self-testing kit for HIV which promises a result in 15 minutes has gone on sale in the UK.
Labour would abolish stamp duty for first time buyers on homes costing up to £300,000, Ed Miliband will announce later.
Chelsea midfielder Eden Hazard has been named England's PFA Player of the Year.