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Nitrate pollution solutions

Planning authority lifts moratorium on determining planning applications after adopting a nitrate ‘credit’ system.

Portsmouth City Council (PCC) has lifted its moratorium on determining planning applications for housebuilding after adopting a nitrate credit system. The end of the moratorium will allow residential development to come forward in Portsmouth and provide an impetus for other Partnership for Urban South Hampshire (PUSH) authorities to adopt similar pragmatic solutions.

In the wake of two rulings by the Court of Justice of the European Union in the ‘Dutch Case’ (C-293/17 and C-294/17) and ‘People Over Wind’ (C-323/17), Natural England (NE) advised local planning authorities in the Solent that uncertainty about the deterioration of the water environment, caused principally by nitrate pollution, had to be addressed in order for the assessment of a planning application to be legally compliant. The uncertainty was caused by nitrate pollution contributing to the excessive growth of green algae (eutrophication) in waters around the Solent.

The advice led five councils in the PUSH area to put planning applications on hold, for fear of having any decisions challenged in the courts. This has prevented residential consents coming forward in recent months.

Following our previous article, PCC held a cabinet meeting to consider an ‘Interim Nutrient Neutral Mitigation Strategy for New Dwellings’. The Strategy (covering the period from 2019 to 2023/2024) detailed three options for mitigating nitrogen drainage when considering planning applications for new residential development:

  1. Offsetting – offsetting against the existing lawful land use on an application site, extant permissions or other land controlled by the applicant.

  2. Bespoke mitigation – other bespoke direct and indirect mitigation measures, agreed in discussion with PCC and NE, such as Sustainable Urban Drainage Systems (SUDS), interception or wetland creation.

  3. Mitigation credit – purchasing of ‘mitigation credit’ from the control of, and water efficiency improvement works to, PCC’s property assets or other recognised source of ‘credit’ in perpetuity.

We understand that PCC intends to generate water savings from existing residential housing within its control in order to build up a bank of nutrient neutral mitigation credit.

It proposes to do this through retrofitting measures (e.g. installing over bath showers and dual flush cisterns) to improve water efficiency and by holding existing facilities due for redevelopment vacant. The savings will allow headroom for the wastewater output of new development and ensure that no net increase in wastewater is sent to protected waters.

Funding for the retrofitting is to be secured by a proportionate contribution from developers via section 106 obligations. Contributions will be sought and pooled from developments of 10 units or more, but will be subject to negotiation based on viability to ensure that affordable housing provision is not prejudiced. Schemes of fewer than 10 units will be subject to a £200 per unit administration and monitoring fee to not disproportionately affect SME builders.


While the credit system is a solution to unlock housing delivery in the Solent and one that has drawn ‘no significant objections’ from NE, it can clearly only be a stop-gap. PCC’s Strategy highlights this by making it plain that mitigation credit is to be used only as a last resort after applicants have fully explored offsetting and bespoke mitigation options and consultation with NE has taken place.

Issues like these are not limited to the Solent either, with Herefordshire Council recently instigating a similar moratorium on housebuilding as a result of NE advice regarding phosphate levels in the River Lugg catchment area.

As noted in our previous article, whilst measures like those detailed above assist, central government needs to pursue reforms to the environmental permitting regime (which regulates discharges from wastewater treatment works) and wastewater treatment practices, rather than putting the regulatory burden on the planning system and development industry.


This information is for educational purposes only and does not constitute legal advice. It is recommended that specific professional advice is sought before acting on any of the information given. © Shoosmiths LLP 2022.


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