Thousands of residents are still facing problems with their water after a "major" burst pipe cut off supply to a large swathe of east London.
Thames Water said that some homes would continue to experience low pressure throughout Wednesday morning following the burst pipe in Hackney Marshes.
Problems continued to persist into the afternoon.
Videos and photos on social media showed supermarket shelves stripped of bottled water as residents stocked up following the outage.
Affected postcodes include E6, E7, E10, E11, E12, E13, E15, E16 and E20.
Thames Water said: "We’ve worked to improve the water supply situation overnight following yesterday’s burst pipe, and pressure is starting to build across our network."
"It’s likely some homes will continue to experience low pressure and this may come and go, particularly during the period of high demand early this morning.
"However, we expect supplies to improve as we move towards midday."
Thames Water added later on Wednesday afternoon that its engineers are working to remove a six-metre section of damaged pipe from woodland in Hackney Marshes.
The burst pipe flooded the area to a depth of 1 metre, which made it challenging for engineers to find the source of the problem, said Thames Water.
The utility company added: "Pressure is continuing to build across the affected area as we continue to work to improve the situation following yesterday’s major burst pipe.
"We’re rerouting water into the area from other parts of our supply network."
Residents took to social media to share their frustration.
One said it was "unacceptable" that much of east London had been without water for "24+ hours".
However, many people said their water had returned by Wednesday morning
Thames Water said engineers worked throughout the night to fix the repair and that they have been using tankers to pump water into the local supply network.
"Our teams are currently prioritising vulnerable customers by delivering water to them, as well as supporting local care homes," the statement said.
"We’re also establishing suitable sites for providing bottled water. We’re really sorry if you still have no water or low pressure.
"We absolutely realise how worrying and inconvenient this disruption is, particularly at this difficult time."
Due to a high volume of calls, Thames Water said it was "prioritising assistance for vulnerable customers and hospitals".
