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
The Prime Minister has created a taskforce and boosted the amount of money available to tackle 'barbaric' modern slavery.
Harry Potter and the Cursed Child will be released around the world at midnight.
The popular HBO TV show will finish after its eighth season, the network said.