Nutrient targets and impacts on your development
In January 2021 Natural Resources Wales published new targets for the concentration of phosphates in Special Areas of Conservation across Wales; additional phosphorus information was published in 2023 followed by other water quality targets in 2024. The revised targets followed evidence from the Joint Nature Conservation Committee that warmer and drier weather, predicted as a result of climate change, could reduce river flows during the summer and, therefore, increase nutrients concentrations. It is based on new evidence about the damaging effect of excess nutrients to water ecosystems and species.
Three rivers within the Bannau Brycheiniog National Park – the rivers Wye, Usk and Tywi – are designated as Special Areas of Conservations and we have produced a map showing the rivers and their catchments in the context on the National Park Boundary. At present, the Wye and the Usk have significant failures against Natural Resources Wales’ phosphorus targets; the Tywi is passing the targets, although with limited headroom. Further details on the status against these targets can be found within the Natural Resources Wales Compliance Assessment report of Welsh River Special Areas of Conservation against Phosphorus Targets Report and the Compliance Assessment of Welsh River Special Areas of Conservation Against Water Quality Targets.
At present, over 60% of waterbodies in Wales fail against the tighter targets, and Local Planning Authorities are being asked to take more action to avoid further deterioration of the environment. This means all future development proposals within failing Special Areas of Conservation River Catchments that will generate an increase in the volume of wastewater must now prove that the ensuing development will not contribute to increased nutrient levels.
Marine Special Areas of Conservation (SACs)
Natural Resources Wales released condition assessments and conservation advice for marine SACs in June 2025.The condition assessments included water quality targets where these could impact on a protected site’s designated features. In marine environments the key nutrient of concern is nitrogen rather than phosphorus. Three out of the seven marine SACs assessed were found to have areas that failed water quality measures for nitrogen. The Burry Inlet Inner waterbody within the Carmarthenshire Bay and Estuaries SAC is one of these areas.
Natural Resources Wales have advised that all further development proposals within the catchment of the Burry Inlet Inner waterbody that will generate an increase in the volume of wastewater must demonstrate that the ensuing development will not contribute to increased nitrogen levels within the Carmarthenshire Bay and Estuaries SAC. The River Loughor has its headwaters within the southwest part of Bannau Brycheiniog National Park and drains to the Burry Inlet Inner waterbody. Consequently, future development within the Loughor catchment will be required to consider the potential for nutrient effects on the Carmarthenshire Bay and Estuaries SAC.The River Tywi catchment drains to the Three Rivers Estuary waterbody within the Carmarthenshire Bay and Estuaries SAC. Natural Resources Wales consider that future development within the Twyi catchment will not be required to consider nitrogen (in addition to phosphorus).
Further details on the Condition assessments for Welsh European marine sites (EMS) and the Conservation advice reports for European marine sites can be found on Natural Resources Wales’ website.
Natural Resources Wales have provided guidance to Local Planning Authorities for the consideration of the impacts of proposed developments requiring planning consent in these nutrient sensitive catchments. Local Authorities must comply with the Conservation of Habitats and Species Regulations 2017 (as amended) and have a statutory duty to achieve the water quality targets and protect the river Special Areas of Conservations through the regulation of activities for which they are responsible.
Development proposals within these catchments, and especially those in proximity to these rivers, may have limited capacity to connect to the public sewerage system or to install private treatment systems. Alternative solutions may need to be found that will meet the new targets, either by meeting nutrient neutrality or providing betterment.
To assist applicants and agents we have developed a Nutrient Statement, which sets out the Authority’s approach in considering planning applications which involve new connections to the larger Wastewater Treatment Works in the Wye, Usk and Tywi nutrient sensitive Special Area of Conservation catchments. Please find our Nutrient Statement dated December 2024
The Authority’s Nutrient Statement (dated December 2024) will be periodically reviewed as new information becomes available – we expect to publish a version 2 of this statement shortly.
Additional Resources
Welsh Government Nutrient Budget Calculator
In June 2025 Welsh Government published a Nutrient Budget Calculator for Wales which can be used to calculate phosphorus and nitrogen mitigation requirements for development within the Wye, Usk and Tywi Special Areas of Conservation (SAC) river catchments. It is understood that the calculator will be updated in due course to inform mitigation requirements for development in other river catchments draining to nutrient sensitive marine waterbodies.
The calculator complete with Welsh Government guidance can be accessed here: https://www.gov.wales/nutrient-budget-calculator
Welsh Government Interim Policy Statement on Development in SAC Rivers and Reminder of Restrictions on Permitted Development Rights in SAC Rivers
On 5th August 2025 Rebecca Evans Cabinet Secretary for Economy, Energy and Planning issued a letter – https://www.gov.wales/sites/default/files/publications/2025-08/interim-planning-policy-statement-on-development-in-sac-rivers.pdf to Heads of Planning across Wales .
This letter:
- published an interim planning policy statement on Development in Special Areas of Conservation (SAC) affected by Phosphorus and signpost the DTA Ecology practical planning guidance https://www.gov.wales/development-special-areas-conservation-sac-rivers-planning-guidance; and
- reminded stakeholders and decision makers of the interaction between permitted development rights and the Habitats Directive and Habitats Regulations outlined in TAN 5 Nature Conservation and Planning (2009).
Further information on permitted development and nutrients can also be found here: https://beacons-npa.gov.uk/planning/nutrients/events-and-permitted-developments/
We will continue to update this page with further information as soon as we are able.