Sewage spill wildlife concerns as water bills rise

Untreated sewage spilling into a village stream has caused a noticeable decline in wildlife, a local resident has said.

Greg Knowlson, who lives next to the treatment works at South Moreton in Oxfordshire, said he had observed the decrease in Mill Brook's trout and otter populations in recent years.

According to Thames Water data, untreated sewage has been released into the brook daily since 3 February - a total of more than 900 hours.

The company said an upgrade for the plant to reduce "untreated discharges" would be complete in 2026.

Thames Water uses rivers as an overflow for when its sewer systems are overwhelmed by rainfall or high groundwater levels.

Mr Knowlson added that his water bills were also going up by about £200 a year: "Then when you see the damage that's been done to these waterways, you're thinking: 'what on earth is going on?'."

Thames Water, the UK's biggest water company, is in financial crisis and has secured a £3bn rescue loan to avoid coming under government control.

Ofwat, the water regulator, says that Thames Water can increase bills by up to 35% - excluding inflation - over the next five years.

But the company says it needs a 53% rise to fix pipes and keep up with demand. It has appealed for permission to charge more.

Thames Water has been providing real-time monitoring on sewage overflows across the Thames basin since 2023.

Whilst the company says data from storm discharge pipes could sometimes be inaccurate, a spokesperson confirmed that the monitor at South Moreton was working correctly.

Mr Knowlson said: "When we first moved here... you could watch brown trout in the bottom of the river for hours on end.

"It's now derelict. There's no fish at all in the river, and no wildlife spotted down the bottom.

"It's really sad."

The Environment Agency classifies Mill Brook's ecological status as 'moderate', with sewage discharge being one of several reasons for the rating.

Thames Water said it was delivering a record amount of investment to address its ageing infrastructure over the next five years.

"This is an enormous undertaking; we are responsible for the oldest and most complex infrastructure of any company in the sector.

"We continue to execute our plans to upgrade over 250 of our sites across the region to increase treatment capacity, lower the number of storm discharges and implement nutrient reduction schemes.

It said an upgrade was planned for South Moreton that would improve its ability to treat the volumes of incoming sewage.

"We are committed to seeing waterways thrive, but we can't do it alone.

"Farming, industry, road runoff, wildlife and increasingly extreme weather also play a role in river health."

On Tuesday, the water regulator Ofwat announced it was investigating Thames Water after the company admitted it will not complete more than 100 environmental schemes funded by customers.

Those schemes included upgrades to sewage treatment works and reducing wastewater spillages.

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