Thames Water surpasses 100km of mains pipes replaced in biggest upgrade for 150 years

• UK’s biggest utility company has replaced over 100km of ageing pipes since April 1, 2025, as it continues with the biggest upgrade to its network in 150 years 
• The length of pipes replaced stretches further than London to Oxford  
• Thames Water on track to replace 550km over five-year programme 

Thames Water has surpassed 100km of mains pipes replacement for its clean water network since the start of AMP8 (Asset Management Period 2025-2030), as the utility company continues its biggest upgrade in 150 years.   

The length of pipes replaced so far stretches further than London to Oxford with Thames Water on track to replace 550km of clean water pipes between 2025 and 2030.  

The UK’s largest water company is investing a record-breaking £20bn to fix leaks, reduce pollution and protect water quality.  

Replacing ageing mains will help reduce bursts, save large amounts of water each year and mean less water needs to be taken from rivers or the ground. It will also lessen traffic disruption caused by ongoing repairs and maintenance, while improving network reliability for future generations with the new pipes having a lifespan of 100 years. 

The milestone was marked in London at a £24m scheme in North London, an 18km project where the landmark was reached in Hampstead. This scheme is an example of the new pipe being laid which is made from plastic which is more durable in the face of environment challenges and increases in demand. 

Mark Taylor, Director of Delivery, London Infrastructure, at Thames Water said: 

“The effects of population growth and climate change are putting increased pressure on Thames Water’s ageing water pipes. Reaching 100km is a great milestone in the biggest upgrade to our infrastructure in 150 years, and this work will deliver real benefits for customers – reducing bursts, cutting water loss and helping to lessen disruption from ongoing repairs and maintenance. 

“Money from customer bills is contributing directly to this work. We are helping to build a strong water system, healthier rivers and top-quality drinking water on tap. 

“We’ve been targeting the areas that need upgrading the most, first, and will be continuing to invest in further mains replacement projects over the next few years. In total, we are going to replace 550km during this AMP, which covers five years in total.” 

With a total of over 140,000km of water pipes and sewers, the Thames Water network would stretch around the world more than three times. There are many ongoing projects across London as the upgrade continues. Other notable schemes include work in: 

• Baker Street 
• Brent 
• Mile End 
• Lambeth 
• Surbiton 

Tim Horton, Major Projects and Programmes Director at Thames Water, said: 

 “We are delivering a significant programme of major capital projects as part of our AMP8 investment period. Improving our water and wastewater network is essential for the delivery of our services and all the work we are doing will bring significant benefits to both our customers and the environment.”