Thames Water says at least 2,000 homes were without water from Saturday morning because of a drop in pressure caused by shutting down the damaged pipe.
The company says the problem was so widespread it did not have the resources both to fix the pipe and send out emergency supplies.
By Sunday evening, supplies were gradually getting back to normal.
The area affected stretches from Stepney to Bethnal Green, Tower Hamlets and Hackney.
Helen Westbury, who lives in Bethnal Green, told BBC London she could not believe people were expected to exist without water.
"There are families around here who can't flush toilets and can't prepare food.
"I rang and complained to the water board, just to find out what's happening, and I was advised I would just have to buy bottled water."
Low pressure
Brian Dean, who lives on the Gascoigne Estate in Hackney, told BBC News Online that his supply came back at low pressure for a time on Saturday evening but went off again on Sunday morning.
"What concerns me is if there was fire on this estate, where will the fire brigade get enough water from?"
He said some local supermarkets were running out of stock of bottled water and he had to go to Islington before he managed to get some.
A Thames Water spokeswoman apologised for the problems and said supplies were gradually being restored.
~RS~a~RS~International~RS~q~RS~~RS~z~RS~27~RS~)