Water Quality - Phosphate

Page updated on: 03/03/2021

Water Quality - Phosphate in Riverine Special Areas of Conservation (SAC) and implications for Planning

Carmarthenshire is characterised by its rich environmental qualities and is home to a number of areas and features designated for their environmental importance including the Afon Teifi and Afon Tywi riverine Special Areas of Conservation (SAC).

Following new evidence about the environmental impacts of phosphate in watercourses, Natural Resources Wales (NRW) have assessed the 9 riverine SACs in Wales. This assessment based on tighter targets for the water quality of watercourses established that phosphorus breaches are widespread within Welsh SAC rivers with over 60% of waterbodies failing against the challenging targets.

As a result of this failure NRW have issued ‘interim planning advice’ to avoid further deterioration in environmental capacity. This ‘advice’ relates to all Riverine SACs whose catchments extend into Carmarthenshire including, the Afon Teifi, Afon Tywi, River Wye and Afon Cleddau. As a Local Planning Authority (LPA), we are required to have regard to the advice given by NRW when making planning decisions (for both individual developments and Local Development Plans (LDP). Consequently, any proposed development within the river catchment that might increase phosphate levels will need to clearly evidence that the development can demonstrate phosphate neutrality or betterment in its design and/or its contribution to the water body. In most cases there will be limited capacity to connect to the public sewerage system and an alternative solution will have to be found. This requirement on drainage considerations will impact on all development that increases the volume or concentration of wastewater.

A map to show the catchment area of the rivers within Carmarthenshire is available to download. In relation to those areas outside the river SAC catchments identified on the map, until further notice please contact the Development Management Team at Carmarthenshire prior to submitting any planning application to establish the impact of the phosphate issue on your proposed development as the map is subject to change at this stage.


Drainage proposals for developments are required to be given significant consideration within these catchment areas. Therefore, prior to an application being submitted to the LPA prospective applicants should engage as early as possible with our pre-application advice service to discuss the acceptability of proposals.

  • NRW have provided interim planning advice for developers. The guidance includes an outline of the type of development which is unlikely to have an impact on phosphate levels in the watercourses.
  • Further and more detailed information can also be found directly on NRW’s website

The NRW advice note outlines, where a planning application within the catchment areas of the Afon Teifi, Afon Tywi, River Wye and Afon Cleddau cannot evidence that the development proposal would result in phosphate neutrality or betterment, that unfortunately the Local Planning Authority would not be able to support the application at this time. This reflects the unacceptable impact on the water quality of the rivers which are sensitively designated as a SAC.

Officers are working on understanding the full implications of NRWs guidance for current planning applications and the progress of the Revised LDP. The NRW advice has significant implications on development proposals within parts of Carmarthenshire and we are working with NRW and our ecology officers to ensure that we are able to progress development proposals that do not harm the environmental capacity of our watercourses. We are also working collaboratively with NRW in understanding the wider issues and identifying the way forward for all proposals, to find solutions that comply with the requirements of the new interim planning advice.

We will update this page with further information as soon as we are able, to keep you informed of progress and to address any frequently asked questions.