River pollution blocking new homes - but why?

It cannot be seen or smelled but a powerful chemical in water courses is blocking as many as 12,000 homes from being built across Somerset.

Levels of phosphate - a form of river pollution which comes from animal and human waste, among other things - are high in the Somerset Moors and Levels.

Large quantities of phosphates in rivers and lakes can effectively deprive plants and animals of oxygen, resulting in fish and other organisms dying.

In 2020 a European Court of Justice ruling meant all development proposals needed be checked over to see if they drive up pollutants - such as phosphates - going into watercourses.

New legal advice is currently being considered by Somerset Council which could unlock those developments, the Local Democracy Reporting Service said.

Here's everything you need to know.

Phosphates can enter watercourses in a number of ways, ranging from fertiliser and animal waste being washed off farmland to human sewage.

The court ruling - called Dutch N - concerns nitrogen and phosphates which are in fertilisers and the limits placed on them to stop them from polluting the wider environment.

The ruling outlaws any developments that increase either phosphate or nitrate levels within wetlands or other low-lying areas which are protected under international law.

Responding to the decision, Natural England wrote to the county's four former district councils highlighting the impact on the Somerset Levels and Moors, as phosphate levels were already high.

Natural England identified 16 "sensitive catchment areas" across the UK where this ruling would apply – including three either in Somerset or on its border.

Those include the catchments of the River Brue, the River Parrett and the River Tone.

Somerset's rivers also flow into the River Axe catchment in east Devon and the Poole Harbour catchment in Dorset.

In order to build any form of new development – from houses and commercial units to agricultural barns – the developer and local authorities would have to agree additional mitigation which would offset the phosphates generated from the proposed site.

To mitigate high phosphate levels, a number of measures have already been put in place.

For example new wetlands - which can filter out and absorb phosphates - have been created, waste water treatment plants have been upgraded and agricultural land has been taken out of active production.

A so-called credit system was created in 2022 which meant developers could pay for mitigation to offset the impact of new homes.

However lawyers have now concluded that the homes could be approved simply by allowing Wessex Water to finish all of the upgrades to its large waste water treatment plans by 2030.

This theoretically means there would be capacity to remove a large amount of additional phosphates which would be generated by future housing growth.

The fresh legal opinion by law firm Landmark Chambers - commissioned by Somerset Council and councillor Harry Hobhouse - effectively rules Wessex Water is "over-engineering" its upgrades.

Somerset Council has said it accepts the opinion and would "provide further information as soon as possible".

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