What we do

The Present 

London relies on a 150-year-old sewer system built for a population less than half its current size.

As a result, millions of tonnes of raw sewage spills, untreated, into the River Thames each year.

That’s where we come in.

We’re building a ‘super sewer’ under the Thames to intercept those nasty spills and clean up our river for the good of the city, its wildlife and you.
But more than that, the Tideway project will bring thousands of jobs, a rejuvenated river economy and completely new areas of public space.

“You’re all part of an underground movement”

The Past

Victorian engineer Sir Joseph Bazalgette created the sewers that we still rely on today after the ‘Great Stink’ of 1858. The sewage pollution into the river at this time was so bad, the smell forced Parliament to leave London until a solution was found.

The result is a magnificent, 1,100-mile network of sewers comprised of more than 300 million bricks.

In 1858, London was home to two million people. Bazalgette had the foresight to build his sewer system for a population twice that size.

However today, the number of people living in the capital is approaching nine million.

So, while the sewers remain in excellent condition, they lack the capacity to meet the demands of modern-day London.

As a result, millions of tonnes of raw, untreated sewage overflow the system and spill into the Thames each year.

The effect on the river’s fish, birds and aquatic mammals is profound.

Ammonia found in sewage harms many of the Thames’s inhabitants, while the bacteria that feed on the sewage deplete the river of oxygen, suffocating many of its fish.

This is shocking and unacceptable.

The Future

Tideway is upgrading London’s sewer system to cope with its growing population. Our 25km tunnel will intercept, store and ultimately transfer sewage waste away from the River Thames.

Starting in Acton, west London, our tunnel (the Thames Tideway Tunnel), will travel through the heart of London at depths of between 30 and 60 metres, using gravity to transfer waste eastwards.

What happen’s London’s sewers when it rains?

Our Locations

Find out more about our site locations along the tunnel line.

Giving back to the community