Thames Water said the outage was caused by a power supply problem at the treatment plants.

The problem was identified at the factory in Ashford and Hampton, west London.

“We are working hard to resolve the issue and get things back to normal,” a statement said.

“We will provide further updates here as we have more information.”

All affected areas so far are in west and south-west London, according to Thames Water.

The supplier has stated that the following postcodes are experiencing supply issues or low pressure:

SW4, SW8, SW9, SW13, SW14, SW15, SW18, SW19, TW1, TW2, TW3, TW4, TW5, TW7, TW8, TW9, TW10, TW11, TW12, TW13, TW14, TW17, W1H, W1H, W1M, W1N, W2, W3, W4, W6, W7, W10, W12, W13, W14

At least two schools were forced to close this morning due to water supply problems.

The Vineyard School in Richmond closed after the water completely stopped.

St Richard Reynolds in Twickenham has also closed, saying “due to water issues the college site has no choice but to close”.

A local MP said she was trying to get more information from Thames Water about when its supply problems would be resolved.

“I’m trying to get more information for local residents and am alarmed that schools are having to close because of this problem,” Munira Wilson, Liberal Democrat MP for Twickenham, wrote on X.

The electricity problem which caused water cuts has been resolved and supplies will be restored to buildings today, a Thames Water spokesperson said.

Water tankers will be sent “as a precaution” to affected areas to “support local hospitals and critical infrastructure”, the spokesperson added.

“Restoring the water supply is our top priority and while our team works on this, we are identifying all people in the affected area who have pre-registered with us as having special requirements, such as being medically dependent on water, so we can get in touch and make sure we get them the help and support they need,” they added.

Thames water has published a list of areas affected by low or no water pressure.

Richmond Council said a total of 14 schools were forced to close due to water supply issues.

Thames Water says the electricity issue causing the problems has been resolved and supplies will return today.

Below is a full list of affected schools.

• Primary Mgr Perrin
• Buckingham Primary
• Carlisle baby
• Christs Secondary
• Kew Riverside Primary
• Nelson Primary
• St Edmunds Primary
• Saint-Jacques Primary
• St Richard Reynolds High School
• Mount Sheen Primary
• Russell’s primary
• Twickenham Primary Academy
• Vineyard Primary
• Waldegrave Secondary

London Mayor Sadiq Khan called on Thames Water to provide “the answers Londoners want about why this happened and how to ensure it doesn’t happen again”.

MPs have called on Thames Water to resolve the problem.

Sarah Olney, Liberal Democrat MP for Richmond Park, said on X, formerly known as Twitter: “I have just learned that some areas of the constituency will have little or no water pressure today today due to a power problem in Ashford and Hampton. Processing works.

“I have contacted Thames Water to ask when residents can expect the problem to be resolved.”