Sadiq Khan accuses Thames Water after three London floods
Thames Water must "up their game" after burst pipes caused three floods in London in a week, London's mayor said.
Hundreds of people were evacuated from their homes and businesses were shut when major flooding hit Stoke Newington, Blackheath and Islington.
Sadiq Khan said people were "rightly furious it appears lessons are not being learnt".
Thames Water has said a "full investigation" will take place "to reduce the risk of further disruption".
Mr Khan said the "huge damage" caused was "a devastating thing to happen in the run-up to Christmas".
"It is right that Thames Water have launched a full investigation, and residents and business must now get full compensation," he said.
Director Bob Collington told the BBC the firm had spent "about £1bn a year upgrading our network" but "clearly the events of the last few weeks point to the fact that we need to do even more".
Some business owners have accused the company of "incompetence" over the floods.
Gonen Ozer, who owns two businesses in Stoke Newington, said the mains had been leaking for several days but the water firm had only "patched it up temporarily".
"I can only describe Thames Water's attitude as reckless, irresponsible and totally unprofessional", he said.
Emily Oliphant was in her Blackheath flooring shop when water started pouring into the building and said the damage caused was "unbelievable".
She accused Thames Water workers of "incompetence" as it took "four or five hours" until the water stopped.
Mr Collington said he was "absolutely devastated about the damage" but denied the company was unprofessional.
He said Thames Water had been "in the process of applying for the permits" to close the road in Stoke Newington to fix the mains when it burst.
With regards to Blackheath, Mr Collington explained that it can take "several hours to shut down one of these large pipes" to reduce disruption to other companies.
"We understand fully the consequences of getting it wrong and we take that really, really seriously," he said.