This excess nitrogen causes:

• Algal blooms and seaweed overgrowth
• Damage to sensitive habitats (mudflats, estuaries, lagoons)
• Harm to wildlife

In June 2025, NRW published assessments identifying three SACs where nitrogen pollution is causing ecological harm. Many of the features of interest for which these SAC’s have been designated are now identified by NRW as being in an unfavourable conservation status and that effectively means that, even though evaluative judgement is required, the possibility of authorising activities which might affect the ecological situation of such sites is practically limited:

• Pembrokeshire Country Council
• Carmarthenshire and
• Swansea

Constructing Excellence in Wales (CEWales) was notified directly by industry of this issue back in June and have been collating data to provide insight on the impact of the current NRW Planning Challenges within the built environment sector. CEWales is providing a view on representing how this issue impacts sector pipelines, schemes of work and associated supply chain matters, focusing engagement on housing and their supply chains. Information is also represented from Contractor, Consultant and SME’s who all form part of the wider supply chain impact.

NRW guidance on marine nitrates has delayed/paused schemes in Carmarthenshire, Swansea and Pembrokeshire in SAC’s. These areas are now subject to nutrient neutrality requirements which can include:

• No additional nitrogen can be introduced by new developments
• Developers must demonstrate nutrient neutrality by:
  • Using the Welsh Government Nutrient Calculator
  • Implementing mitigation measures (e.g. nature-based solutions, improved drainage, upgraded sewage treatment)
  • Submitting a Habitats Regulations Assessment (HRA)
  • Planning authorities can only approve developments that show no adverse impact on the SAC

This has affected projects: ranging from pre-determination, various stages of work, including expensive survey work, ecology, topographical etc, those in a build contract, those legally tied into purchases and well progressed with planning applications that are now on hold,  those which have secured terms and were looking to progress planning applications within the next few months. Thank you to those of you who have already supplied us with intel however the true Impact on business and people is significant and is an emerging picture; please do get in touch with us if you have any information to add.

A complex picture

As noted in Nutrient Neutrality And Welsh European Marine Sites | Hugh James, NRW’s June 2025 assessments concluded that the nutrient-sensitive features of sites such as Pembrokeshire Marine, Carmarthen Bay and Estuaries, and Cemlyn Bay are failing to meet conservation targets. Excessive nitrogen is contributing to algal blooms, reduced oxygen levels, and negative impacts on fish and other aquatic life.

This mirrors the position in England, where Natural England issued similar advice in 2020 (following the Dutch Nitrogen Case) to advise local planning authorities that mitigation measures forming part of a Habitats Regulations Assessment must demonstrate no adverse effect ‘beyond reasonable scientific doubt’ and that the benefits of the mitigation measures must be ‘certain at the time of the Assessment’ before consent can be granted. The advice resulted in new development being required to achieve ‘nutrient neutrality’, where the nutrient load created through additional wastewater from development had to be mitigated, either on-site or off-site. Importantly, previously consented, as well as existing schemes are caught here. This includes LPAs discharging planning conditions, approving reserved matters or granting minor amendments to existing planning consents.

What does “nutrient neutrality” mean in practice?

Nutrient neutrality requires that any increase in phosphate or nitrogen discharges from new development is fully mitigated, so that there is no net increase in nutrient loading in affected catchments.

Mitigation may include:

• on-site options such as sustainable drainage systems, wastewater treatment works and habitat creation; or
• off-site options such as nutrient trading schemes, land use changes/rewilding secured by conservation covenants and upgrades to wastewater treatment works

NRW’s advice is clear: a conclusion of no adverse effect on site integrity may only be reached if nutrient neutrality can be demonstrated.