Why we are replacing pipes

About 12 per cent of London's water mains are over 150 years old - and more than 40 per cent over 100 years old.

Although we have made major investment over the past ten years, water pipes in many areas of London are still among the oldest in the UK, and they need replacing.

This work is particularly important, as London's water resources are being put under increasing pressure from the effects of climate change and because the capital's population is growing.

Although the original Victorian, cast iron mains have served us well, they're old and more likely to leak or burst. We are therefore replacing the oldest, leakiest pipes first with tough new plastic ones.

Although the work inevitably involves some short-term disruption, it will bring many long-term benefits - most importantly, a reduction in the potential for future bursts and leaks, minimising the need for more repairs and roadworks in the future.

What we are doing

So far, we have replaced over 1,300 miles of old and leaky water mains in London and in any given week, we are working in up to 300 streets in the capital.

In the areas where pipework needs to be replaced, we carry out detailed investigations using state-of-the-art computer modelling to find the best way of renewing the pipe network.

Where possible, we use 'no dig' technology that avoids the need for long trenches.