UK heatwave: London water firms hold off on hosepipe ban

London experienced the second driest July on record last month

Two London water firms will not introduce a hosepipe ban, despite dry weather having a "large impact" on water levels.

SES Water and Affinity Water, which serve south London and north-west London, respectively, store most of its water in underground aquifers, making it less likely to evaporate.

It comes after Thames Water announced a hosepipe ban in the coming weeks.

The Met Office has issued an amber extreme heat warning for England.

Last month, rainfall in Thames Water's catchment area was down 52mm (2.5 inch) on average.

It was the second driest July on record, with many London reservoirs being 75% full - below average for the time of year.

Only 25% of Thames Water's supply is sourced from aquifers, while the rest is sourced from rivers and reservoirs.

The company currently leaks 24% of its water, and did not respond to BBC London's approach to whether this was a key factor in opting for a hosepipe ban.

Analysis: Tom Edwards, BBC London environment correspondent

Water companies in London and the South East have a different mix of where they get their water from - rivers, reservoirs or underground water-bearing rock called aquifers.

That means they're all in a different state when it comes to supply. Affinity and SSE Water think hosepipe bans are unlikely - they use aquifers mainly - but Thames Water says it will have to introduce a ban in the coming weeks as it is reliant more on rivers and reservoirs.

The rumours in the industry are a drought could be declared by the end of the week but it's still up to the water companies to manage their supplies how they see fit.

All the companies are monitoring usage, storage and rain very closely and the picture could change quickly - all of them are asking customers to use water responsibly.

In a statement, SES Water said: "Around 85% of our water comes from groundwater sources, and although these have also been affected there's less chance of the water evaporating like it does from reservoirs."

Bough Beech Reservoir in Kent, which is owned by SES Water, is 11% lower than expected at this time of year

"While some of the neighbouring water companies have announced hose pipe bans, we are not yet at that stage," a spokesperson added.

"We will of course keep the need for any restrictions under close review for the rest of the summer period, however this will depend on the rate of decline of our groundwater and reservoir sources, and the level of customer demand."

Similarly, Affinity Water said it was keeping an eye on the situation and was dependent on rainfall over the upcoming autumn and winter period to refill groundwater aquifers for 2023.

Temperatures are set to reach up to 35°C (95°F) in some areas this week.

The Met Office has issued a four-day amber extreme heat warning which applies to southern and central England and parts of Wales from midnight on Thursday until Sunday.

It follows the first-ever red warning issued in July, when temperatures exceeded 40°C for the first time.