Could Somerset phosphates crisis be solved by Wessex Water upgrades?

Around 12,000 homes across Somerset are currently in limbo due to the phosphates crisis, with the Dutch N court ruling (and Natural England legal advice) prohibiting any development which increases phosphate levels within the Somerset Levels and Moors catchment area.

Somerset Council has managed to approve or ‘unlock’ around 6,000 new homes through ‘phosphate credit’ schemes, where developers pay for phosphates to be offset elsewhere in the catchment through the fallowing of agricultural land.

Other forms of legally required mitigation are also being explored, from the creation of new wetlands to growing miscanthus grass on the Levels, using a £9.6m grant from central government.

But councillor Henry Hobhouse has revealed that all the remaining homes could be delivered as part of Wessex Water’s ongoing upgrade of its waste water treatment plants across Somerset – rendering all the phosphate credit systems totally redundant.

Somerset Council said it was awaiting legal advice on the matter and would press on with its existing proposals until such advice had been obtained.

Here’s everything you need to know:

What is the phosphates crisis?

Phosphates can enter rivers and other watercourses through a number of methods, ranging from fertiliser and animal waste being washed off farmland to human sewage.

Large quantities of phosphates in rivers and lakes can cause eutrophication and large algae blooms, which can deprive plants and animals living in these habitats of oxygen.

The Dutch N court ruling outlaws any developments which increase either phosphate or nitrate levels within Ramsar sites – that is, wetlands or other low-lying areas which are protected under international law.

The Somerset Levels and Moors (red) and the affected catchment areas (blue). (Image: Somerset Council) The resulting legal advice from Natural England, which was published in August 2020, identified 16 “sensitive catchment areas” across the UK where this ruling would apply – including three either in Somerset or on its border.

In addition to the Somerset Levels and Moors (which includes 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 the local authorities would have to agree additional mitigation which would offset the phosphates generated from the development site.

What has been tried to date?

To date, phosphate mitigation has taken a number of forms, including:

• Creating new wetlands, which can filter out and absorb phosphates (such as at the Staplegrove urban extension in Taunton)
• Fallowing agricultural land, taking it out of active production and potentially replacing it with woodland (such as the Canal Way development in Ilminster)
• Upgrading waste water treatment plants, removing phosphates from sewage (such as at the Lowerside Lane site in Glastonbury)
• Upgrading septic tanks with package treatment plants, which take more phosphates out before they leave a residential area (such as at the planned Nynehead Road development in Wellington).

Both Somerset Council and private companies have also created ‘phosphate credit’ schemes, whereby the developer will pay for off-site mitigation to offset the impact of new homes.

To date, this has often taken the form of farmland being taken out of active use – with the fallowing of Manor Farm in Prestleigh, near Shepton Mallet, generating enough credits to unlock up to 1,400 new homes within the River Brue catchment.

In addition, the council secured £9.6m in central government grants in December 2023 to fund half a dozen projects designed to deliver further mitigation – namely:

• A water filtration technology pilot, using reverse osmosis technology from Salinity Solutions to filter out water-borne phosphates (£2m)
• Identifying new nature-based solutions (such as wetlands) where biodiversity net gain can also be delivered (£3.5m)
• Retrofitting social housing, including the removal and replacement of septic tanks in older properties (£1m)
• Creating nature-based solutions on council-owned land, including the creation of new nature reserves on existing green spaces (£2m)
• Growing miscanthus grass on fallowed land to generate additional phosphate credits (£640,000)
• Researching and developing new technical innovations which could be scaled up in the near-future (£400,000).

Why is councillor Henry Hobhouse unhappy?

Mr Hobhouse is one of two Liberal Democrat councillors representing Castle Cary and the surrounding villages – an area which saw significant housing growth in the years before the Dutch N ruling.

At a meeting of the council’s strategic planning committee in Taunton on Monday morning (September 16), Mr Hobhouse revealed he had obtained legal advice from Landmark Chambers which cast considerable doubt on whether the council’s phosphate mitigation efforts were effective or even necessary.

He said: “Natural England is not in charge, it’s the council. It is no good us saying that this is not our problem – we are in charge of this particular situation.

“We need to be looking at the other scientific options. Natural England cannot take us to court if we can prove that their advice is flawed.

“This is proven in a case where Cornwall Council went ahead and allowed 400 homes to be built in Bodmin.

“We only have to prove that our mitigation does not add to the pollution on the Ramsar site.”

Mr Hobhouse said his legal advice also stated you could “use sewage as a mitigant” – in other words, that removing phosphates by upgrading waste water treatment plants could be counted as mitigation.

This, he argued, would remove the need to fallow agricultural land or the entire phosphate credits system.

He added: “You’re proposing to use reverse osmosis to remove phosphates from the output of sewage plants. Why are you not taking account of Wessex Water’s excess removal [using their own technology]?

“Wessex Water will remove 5.6 tonnes of phosphates [from the system through their upgrade] – which more than covers the 3.2 tonnes required to mitigate the whole 18,000 houses [that have been delayed since 2020].

“There is existing work being done by the Farming and Wildlife Advisory Group (FWAG) and the Royal Society for the Protection of Birds (RSPB) on one of the Ramsar sites, which includes trialling miscanthus grass. Why are you spending grant money to replicate these trials?

“Less than ten per cent of the water from the river catchments actually gets onto the Ramsar site.”

What is Wessex Water planning with its upgrades?

Under the Levelling Up and Regeneration Act 2023 (known colloquially as LURA) water companies were commanded to upgrade their waste water treatment plants to remove larger quantities of phosphates than was originally permitted.

The upgrades must be implemented by May 2031 and must be applied to all waste water treatment plants which serve a population of 2,000 or more people – meaning some of the smaller plants (such as Ansford, near Castle Cary) will still release relatively high amount of phosphate after sewage has been processed there.

The following plants will be upgraded under LURA:

• Bishop’s Lydeard
• Bruton
• Butleigh
• Castle Cary
• Chard
• Crewkerne East
• East Coker
• Evercreech
• Glastonbury
• Ilchester
• Ilminster
• Langport
• Martock
• Merriott
• Milborne Port
• Shepton Mallet
• Sherborne
• Somerton
• South Petherton
• Taunton
• Thornford
• Wellington
• Wells
• Yeovil (Pen Mill site)

However, Wessex Water has committed to completing these upgrades by April 1, 2030 – more than a year ahead of schedule.

The company has also entered into an agreement with the council to implement “stretch permits” at its Langport, Taunton and Wells site which will see additional phosphates removed on top of the LURA requirements.

Wessex Water has corroborated Mr Hobhouse’s information, stating that their agreed upgrades would go above and beyond the levels required by the government – thereby allowing all the outstanding homes to be delivered without phosphate credits or other mitigation.

A spokesman said: “Councillor Hobhouse is correct to assert that our treatment sites outperform their discharge permits, outweighing any additional phosphorus from new developments.

“How this is accounted for in planning decisions surrounding nutrient neutrality requirements is a matter of policy for the planning authority.

“Our upgrades to our treatment sites are intended to meet tighter discharge standards laid down by both environmental and economic regulators.

“Bills and how and where we invest to meet new environmental standards are also determined by the industry regulator Ofwat.”

Do other councillors share Mr Hobhouse’s views?

Mr Hobhouse’s revelations struck a chord with numerous councillors across the political spectrum.

Councillor Simon Coles (Lib Dem, Taunton East) said: “Wessex Water, through voluntary agreements, tell us they have removed 5.6 tonnes of phosphates, and we only need 3.2 tonnes of phosphates to deliver the 18,000 homes.

“I don’t understand why we can’t use that headroom that Wessex Water have told us they have created to overcome the phosphate issues. It doesn’t make sense to me.

“If Wessex Water is correct, then we do not have anything like the phosphate problem that we think we’ve got.”

Mr Coles chairs the council’s planning committee west, which has approved numerous large housing developments within the former Somerset West and Taunton area – including elements of the Orchard Grove urban extension in Taunton, and 200 homes needed to deliver the access road to the proposed new railway station in Wellington.

Councillor Martin Wale (Conservative, Chard North) said: “I’m always a bit suspicious about legal advice, because it all depends who you go to.

“Having done a lot of it in my past life [as a police officer], we shall see. But Henry has brought some interesting points up.”

Mr Wale’s division includes a proposed development of 295 homes and the relocation of Chard Town Football Club to a new stadium off Thorndun Park Drive – a development which has been repeatedly delayed by the phosphates issue.

Councillor Matt Martin (Lib Dem, King Alfred) said: “I sit here somewhat awed by Henry’s knowledge, enthusiasm and dedication in tracking this stuff down.

“I do feel that we mustn’t lose sight of the fact that this whole question has a root in us finding a satisfactory way of allowing Somerset to prosper while protecting our rivers and wetlands.

“I worry that we’re going down rabbit holes and behind looking-glasses to look at legislation, offsets and costings.”

Mr Martin serves as vice-chairman of the council’s planning committee north, which makes decisions on major plans within the former Sedgemoor area – much of which has been unaffected by the phosphates issue.

Councillor Sue Osborne (Conservative, Ilminster) said: “We get a lot of applications coming forward in the rural areas. What work is being planned to ensure that these smaller waste water treatment plants can also be brought up to date?

“What’s going to happen is that there is going to be a very big difference in  the cost of phosphate credits between the urban and rural areas. It’s a question of whether these extra plants can cope with these extra developments.”

Councillor Michael Dunk (Green, Frome West) said: “We know there’s pollution – it’s been tested, we’ve got too much phosphates in our rivers.

“But the people we’re relying on (the EA and Natural England) have not been fully funded enough to work out each specific problem in any level of detail.

“I wonder if we need to spend some of that government money on doing our own research to find out exactly where the pollution is entering the system and in what quantities. We’re stabbing in the dark here.”

Councillor Tony Lock (Lib Dem, Yeovil East) – who chaired the committee meeting – said: “Henry is very knowledgeable on this subject, but it doesn’t mean he’s right on everything – the same goes with our officers.

“Legal advice has been sought by Henry as an elected member, and he is quite entitled to do that. We as a committee are guided by our officers and the legal advice we are given.

“We may not agree with it, or want to support it at the end of the day, but while that [additional] legal advice is in abeyance and not with us at this moment in time, we cannot do any more than what we’ve got.”

How has the council’s planning team responded?

Kate Murdoch, the council’s service manager for planning policy and implementation, she said the situation in Cornwall (which concerns the River Camel catchment) “doesn’t apply to the Somerset Levels and Moors”, referencing a briefing note circulated to councillors in February.

While noting there was only an “extremely slim” chance of Natural England taking the council to court, she said departing from the established advice could lead to other potentially expensive legal challenges – including from the companies selling phosphate credits to developers.

She said: “I would suggest that the larger risk for a legal challenge comes potentially from residents’ action groups, who would want to understand why we would be choosing to move away from the advice from Natural England.

“A legal challenge could also potentially come from the increasing third party environmental credit market, which the council has supported.”

The council has already faced a number of legal challenges in recent years, including a successful judicial review into the Mendip Local Plan Part II which led to five housing sites being scrubbed and alternative land needing to be found to meet government housing targets.

Ms Murdoch said that Natural England had “signed off” on all the council’s existing phosphate mitigation schemes, adding: “We have to ensure that each additional dwelling that we give permission for is not increasing the nutrient load.”

Regarding the legal advice, she commented: “Mr Hobhouse’s legal advice does not align with the council’s legal advice, and so we are getting further legal advice.

“The two legal opinions aren’t that different, in legal terms; it is the evidence which underpins it, and on which the council would need to rely if it was taking a different approach.

“At the moment, the approach we are taking is on the basis of the advice from Natural England. To date, there hasn’t been evidence supplied to verify a different approach.”

Ms Murdoch said she was “fully aware” of the ongoing FWAG/ RSPB trials, but said these did not involve miscanthus, based on discussions with both bodies.

What happens next?

Further discussion of the phosphates crisis is expected to take place at a meeting of the council’s climate and place scrutiny committee (on which Mr Hobhouse sits) in Taunton on Monday morning (September 23).

This committee had made numerous recommendations to alter the council’s approach to the phosphates issues – but these were shot down by the council’s executive committee in early-June.

A formal update on the additional mitigation measures being pursued using the £9.6m government grant will be brought before the strategic planning committee in March 2025.