Thames Water urged to fix leaks before swapping out river water with treated sewage

Image above: A burst water main on Bath Road in January 2023

Agency criticises plans to swap 75 million litres of water from Teddington weir with treated sewage 

Thames Water has been told by the Environment Agency it needs to do more to fix the 630m litres of water lost in leaks each day before it starts taking water from the River Thames or from Wales to tackle drought problems.

The water firm says it needs to increase domestic water supplies to cope with a rising population and the risk of future droughts and has proposed taking 75 million litres of water a day from the Thames upstream of Teddington Weir and replacing it with treated effluent

The Environment Agency warned the company must justify it is making the right decisions, especially when the proposed scheme carries “substantial risk”. Thames Water itself has previously admitted replacing the water with treated effluent potentially poses a threat to river life.

READ ALSO: Plans to swap out water from River Thames with treated sewage meet resistance

The company has made a number of proposals and set up public consultation meetings at various points along the Thames, from Cirencester, to Oxford, Abingdon and Reading. There have been meetings in Paddington and Richmond, but nothing organised in Brentford or Chiswick by either Thames Water or Hounslow Council.

The Environment Agency said alternative schemes would cost more but the company “needs to consider whether the short-term costs are outweighed by better long-term benefits”. It also warned the security of water supply will be at risk if the company does not drastically reduce leaks and customer demand for water.

Image above: A burst water main at Chalker’s Corner in December 2022

Thames Water leaks “more water than any other company”

Thames Water’s initial version of the scheme was rejected in 2019 over concerns about unacceptable impacts on the environment. The Environment Agency said Thames Water had reintroduced the scheme and made “substantial improvements”, but it still has reservations about the impact on the environment and long-term viability.

The report says:

“Given that the Teddington direct river abstraction has not yet been shown to be feasible or environmentally acceptable, the company should ensure alternatives are progressed. Thames Water should ensure any options selected are resilient, reliable and do not cause any adverse environmental impacts.”

The Environmental Agency also urged the company to explore how to “substantially reduce leakage” beyond the 50% reduction target it has set by 2050.

It said Thames Water “leaks more water than any other company” and while it welcomed the company’s ambition to reduce leaks, added it “must demonstrate it can deliver its ambition”.

Image above: Artists impression of the drainage infrastructure planned for the River Thames

Environment Agency urge Thames water to “develop alternative options”

An Environment Agency spokesperson said:

“The whole of the South East is determined as being in serious water stress. Climate change and population growth mean we need to take action now to ensure resilient water supplies are available to meet the needs of all users in the future.

“We require further evidence that the direct river abstraction proposal put forward by Thames Water would not have adverse impacts on the environment, along with proof of its long-term viability in light of climate change.

“We urge Thames Water to produce this evidence as quickly as possible and develop alternative options to ensure that it can deliver a secure supply of water for its customers for the next 25 years and beyond.”

Images above: sewage in the River Thames by Chiswick Riverside 

Thames Water claim water quality will not be negatively impacted

Thames Water claim they have met leakage reduction targets for the last three years, cutting leaks by more than 10% from 2017/18 levels and aiming for a 50% reduction by 2050. A Thames Water spokesperson said:

“Reducing leakage is a priority for us and is one of the foundations of the plan. Even with an ambitious target of halving leakage by 2050 we still need more storage in the future to account for growing population demand and climate change.”

“We are repairing over 1,300 leaks per week – whether they are visible or hidden below ground across 20,000 miles of pipes across our network – that’s one leak every 7.5 minutes. We’re also working with our customers to reduce leakage from their water pipes, which make up a third of our total leakage.”

Thames Water said the Teddington scheme is only a potential option, along with others including a new reservoir near Abingdon and water transfer from the River Severn to the Thames, and that it would not negatively impact water quality. The spokesperson added:

“We’ve worked closely with the Environment Agency throughout the consultation process and in developing the scheme. We are now carefully reviewing their feedback on our draft water resources management plan, including comments regarding proposed river abstraction at Teddington.

“As the scheme is only at the conceptual design stage the precise locations have not been confirmed. If the scheme is taken forward, there will be detailed option appraisal and design work, where we will carry out engagement and consultation with the local community.

“The scheme will not negatively impact the river water quality. The treated wastewater effluent taken from Mogden sewage treatment works would go through an additional stage of treatment to ensure there is no deterioration to the water quality in the river. This would also compensate for the volume of water abstracted from the river.”

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