Brixton Hill water supplies return after burst main
Up to 50,000 properties lost their water supply for 12 hours after a main burst on Brixton Hill in south London.
The pipe caused flooding on the hill and in Elm Park from about 0530 BST.
Thames Water apologised and said the repairs had been complicated by damage to a gas main, which also occurred as a result of the burst.
The A23 Brixton Hill remains closed to traffic and it is feared the southbound side may be shut until Saturday so repairs can be completed.
But it is hoped the northbound carriageway will reopen before Friday morning.
"All water supplies have now been fully restored following a major burst water main in Lambeth today, which left customers in SW, SE and CR postcode areas with no water or reduced water pressure," the utility firm said in a statement.
"We restored supplies as quickly as we could by redirecting water from other areas.
"Unfortunately the burst resulted in damage to a gas main, which has delayed our own repairs.
"Gas engineers have been working all day to repair the pipe and at 4pm we were able to gain access to fix our main."
It said its staff would work throughout Thursday night to complete the work.
Three primary schools and a nursery in the borough of Lambeth were closed owing to the lack of water.
People in Brixton, Tulse Hill, Putney, Streatham, Tooting, Wimbledon, Raynes Park, Merton, Dulwich, Forest Hill, Sydenham and West Norwood were worst affected.
London Fire Brigade said it had attended 20 flooding incidents on Thursday, a number of which were caused by heavy rain.