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Secret underground reservoir revealed

Tuesday 24th December 2019 12:00

One of Thames Water’s most spectacular structures – hidden under ancient woodland in London – was revealed in all its Victorian glory during work to maintain the exceptional standard of the company’s drinking water.

High Beech, an underground reservoir in the middle of Epping Forest, was built in 1887 and normally stores 10 million litres of treated water before it is pumped to the taps of 18,000 customers across the region.

At four metres deep and covering an area of 2,800 sq metres, the arched Victorian structure was drained to allow engineers to carry out £100,000 worth of maintenance ahead of the festive period.

Diane Barlow, of Thames Water’s water production operational excellence team, said: “We take our responsibility in providing customers with the high-quality water supply they rightfully deserve very seriously, so we were determined to get it right first time. This work protects water supplies for now and future generations.

“The reservoir was in pretty good condition considering it’s more than 130 years old. The attention to detail and beautiful craftsmanship of the Victorians who built it never ceases to amaze us.”

With the main reservoir out of action, a reserve tank ensured supplies were maintained to customers, with teams working extended hours to ensure the project was completed as quickly as possible in time for Christmas.

Diane added: “This was all with a view to keeping the outage as short as was practical, and therefore minimising any risk of customers going without water. As it turned out it was very successful with no customer impact. We’re learning from our successes to ensure the next reservoir inspection goes just as smoothly.”

Thames Water has approximately 320 service reservoirs and 520 individual cells on an inspection programme, as required by law, and typically inspects 60 cells per year. The company also tests its drinking water over 500,000 times every year, which helps to make it some of the highest quality in the world. The Drinking Water Inspectorate (DWI) also carry out their own tests to make sure the water always meets industry regulations.