Somerset Council will spend £1m upgrading sewage treatment plants near rural council houses as part of wider measures to unlock new homes.

Around 12,000 homes across Somerset remain in limbo as a result of the ongoing phosphates crisis, with the council and developers having to agree additional mitigation to prevent any net increase in phosphates within the Somerset Levels and Moors catchment area.

The council received £9.6m in government grants in December 2023, which has been allocated to a number of different schemes – including the creation of new wetlands on council-owned land and growing miscanthus grass (which can absorb relatively large quantities of phosphate).

The council’s executive committee has now agreed to spend £1m of this grant on upgrading five sewage treatment plants near Taunton and Wellington, which will allow additional development sites in the catchment to be unlocked.

The majority of waste water treatment plants across Somerset are owned and operated by Wessex Water, which is undertaking its own upgrades over the next seven years.

However, 20 small-scale plants (known as package sewage treatment plants) are owned and maintained by the council, with the majority being in the former Sedgemoor and Somerset West and Taunton districts.

Most of these small-scale plants are 40 years older or more and are reaching the end of their operational life – with the council legally bound to maintain them even if the council houses they originally served are now privately owned.

The council intends to use £1m from the government’s grant to upgrade the five “worst performing plants” in its ownership – namely those serving the following development sites:

  • Meadowsite, Combe Florey
  • Castle View, Curland
  • Weekes Meadow, Sampford Arundel
  • Appley Cross, Stawley
  • Homefield, Stoke St. Mary

By upgrading these five plants, more than 28kg of additional phosphates per year will be removed before they enter the River Parrett and River Tone catchment areas.

By removing these phosphates at this juncture, developments within both catchments can be brought forward, reducing the backlog of planning applications at the council and easing the local housing crisis.

Councillor Federica Smith-Roberts, portfolio holder for communities, housing revenue account, culture, equalities and diversity, addressed the matter when the council’s executive committee met in Taunton on October 7.

She said: “Some of the properties are now in private ownership through the right to buy, but we do own these treatment plants and this is a good use of the money to mitigate the impact that phosphates are having in these catchment area.

“For me, it’s positive that we are now able to move this forward – I believe this has been discussed for at least the last 18 months to make this happen.”

The council said it could not specify which sites would be unlocked through these improvements, stating it would depend on how developers bid for phosphate credits generated by the work.

Shane Smith, the council’s housing revenue account development manager, said: “With this arrangement, we are selling phosphate credits to our colleagues within our climate team – and I don’t know how those credits are then sold or prioritised on the market.

“We are just being procured to produce those credits and then passing them on to our colleagues.

“The credits will be passed on as and when the upgrades are completed.

The work is expected to be carried out from April 2025 onwards, meaning the phosphate credits generated will be available for developers to purchase from the summer of 2025 onwards.