Public asked for views on updated reservoir plans

An artist's impression of the planned reservoir which would cover an area roughly the size of Gatwick Airport

The UK's largest water company has launched a public consultation into plans to build a reservoir that it says would secure supplies for 15 million people.

Thames Water wants to start construction on its South East Strategic Reservoir Option, near Abingdon, in 2029 - with the reservoir operational from 2040.

It said the reservoir, which would cover an area roughly the size of Gatwick Airport, could provide the equivalent of three million baths every day during droughts.

An 11-week public consultation into the scheme began on Tuesday.

Leonie Dubois, from Thames Water, said the consultation was "the most significant milestone in our reservoir journey to date".

"Public feedback will shape our application for planning consent, which we will submit to government next year," she said.

Customers of Thames Water, Affinity Water and Southern Water will pay for the new reservoir through their bills.

Thames Water's Strategic Water Resources Director, Nevil Muncaster, said about £5 a month would be added to bills by 2040.

The consultation runs until 13 January 2026, and includes seven in-person events in Abingdon, Wantage and Didcot in November.

Proposals including the creation of about 62 miles (100km) of paths, bridleways, tracks and cycleways between nearby villages are part of plans being put to the public.

Plans to install floating solar panels within the reservoir site and the creation of "priority biodiversity areas" are also being proposed.

Thames Water said the public input from the consultation would "directly inform" its application for planning consent from the government, which it plans to submit in autumn 2026.

"Our proposed reservoir is one of the most vital infrastructure projects in the country," Ms Dubois said.

"It will safeguard water supply for millions of people across the South East, including local communities, protecting our precious rivers and groundwater sources in the process."

A claim for a judicial review into the scheme from local campaigners opposed to the plans was thrown out by the High Court earlier this year.

Countryside charity CPRE Oxfordshire and water safety group Safer Waters, who brought the claim, said the reservoir would devastate local ecology and livelihoods.

Thames Water previously said building the reservoir would cost between £5.5bn and £7.5bn, while it would cost £1.9bn to run for its first 65 years.