Thames Water will now have to declare at the outset of planning applications whether the sewage treatment works can cope with the extra homes.

West Oxfordshire District Council has changed its planning regulations so that where there is insufficient capacity, a planning condition will be added to require that the new homes are not occupied until the works have been upgraded.

Buyers and solicitors will be made aware of this condition upfront. 

Thames Water has also agreed to respond to planning applications for all developments where there is insufficient treatment capacity rather than just the larger ones.

Cllr Lidia Arciszewska, Executive Member for Environment, district councillors Charlie Maynard and Alaric Smith, council officers and Thames Water have been working together over the past six months on steps to reduce sewage pollution in local waterways.

Ms Arciszewska said: “The current situation is not acceptable."

Thames Water's interactive map of storm discharges showed that Hardwick Brook in the Rushy Common nature reserve near Witney had almost four days of sewage dumped into it over a week in January, making it the worst in the Thames Water region.

The spills came despite only 3mm of rain over the period.

Thames Water has announced plans to spend a record £1.6billion over the next two years on upgrading sewage treatment works and sewers.

This is more than double its investment in sewage related infrastructure in the previous two years.

One of the key projects is the £15million expansion of Witney Sewage Treatment Works, which currently serves 45,000 people, expected to be complete early in 2024.

Thames Water says the upgrade will provide a 60 per cent increase in capacity.

But the council team also has concerns that Thames Water's calculations are 'optimistic'  on data such as the amount of water used by each person that ends up in the sewage system.

Ms Arciszewska, a retired Oxford University biochemist, added: "Thames Water appears to be applying a multiplier below the Environment Agency’s recommended 3.0x in its capacity calculations.

"Both of these actions potentially lower the estimated required capacity of the sewage treatment works and, therefore, not enough is invested in improving the sewage treatment capacity."

In addition to future capacity being a problem, the council has been told that over 40 per cent of the waste in sewage plants is coming from water getting into the sewer system through leaky pipes and manholes.

Ms Arciszewska said they want further information from Thames Water on what steps they have been taking, and how they plan to address this issue.

Ms Arciszewska said: “In some cases, such as Witney, Thames Water has provided a clear action plan for addressing capacity - in other cases, such as Carterton, Cassington and Woodstock, these are still to come.

“We need Thames Water’s commitment to fund solutions which address these serious problems now."

 

Read more from this author

This story was written by Miranda Norris, she joined the team in 2021 and covers news across Oxfordshire as well as news from Witney.

Get in touch with her by emailing: Miranda.Norris@newsquest.co.uk. Or find her on Twitter: @Mirandajnorris

Profile: Miranda Norris Journalists news from the Oxford Mail