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Nutrient Neutrality

This page provides information and updates in relation to the requirement of developments to demonstrate Nutrient Neutrality, as set out in updated advice provided by Natural England on 16 March 2022.

Please use the following links for further information, updates, and for the latest position for each catchment area:

Dorset Council have produced a guidance note for new and replacement septic tanks and package treatment plants which sets out how proposals will be considered in the context of nutrient neutrality. This guidance note has been produced with input from the Environment Agency, Natural England and Wessex Water.

Natural England’s advice of 16 March 2022

On 16 March 2022, Natural England notified Dorset Council of their updated advice for development proposals that have the potential to affect water quality resulting in adverse nutrient impacts on internationally protected habitats sites. This advice applied to the catchments of five habitats sites which together cover a large part of the Dorset Council area. The advice was that Dorset Council should “carefully consider the nutrients impacts of any new plans and projects (including new development proposals) on habitats sites and whether those impacts may have an adverse effect on the integrity of a habitats site that requires mitigation, including through nutrient neutrality.”

The catchment areas within Dorset that this advice related to are:

Although the issue of nutrient pollution is not new, Dorset Council is working with the other councils across each catchment and with Natural England to understand the implications of this updated advice for future development.

This early work is ongoing and as things progress this web page will be updated.

The Natural England updated guidance includes a Generic Nutrient Neutrality Methodology for calculating nutrient loads in each of the habitat site catchments in our area and a catchment calculator for each catchment. These tools are provisional and the methodologies and assumptions within them will need to be reviewed to reflect local circumstances. In some instances, local methods and calculators have already been developed to calculate nutrient loading from development. Pending our detailed review and in the interim, all developments will need to demonstrate nutrient neutrality.

Further information and guidance from Natural England is available:

Written Ministerial Statement of 20 July 2022

On 20 July 2022, a Written Ministerial Statement was made by the Secretary of State for the Environment, Farming and Rural Affairs about a package of measures to address Nutrient Neutrality across England. In addition to the Written ministerial Statement, a Chief Planner letter was issued by the Department for Levelling-up, Housing and Communities and Dorset Council received a letter from Natural England.

The two main measures announced were:

  • The intention to table an amendment to the Levelling Up and Regeneration Bill to require the upgrade of all wastewater treatment works within the affected catchments
  • A nutrient mitigation scheme to be managed by Natural England aimed at delivering nutrient mitigation within the affected catchments

Within this material there was also clarification of which post permission approvals are caught by the nutrient neutrality advice.

Dorset Council is working closely with Natural England, DEFRA and DLUHC to fully understand the implications of these announcements and how the national nutrient mitigation scheme will operate in Dorset.

Designation of Nutrient Sensitive Catchments

On 25 January 2024, the Secretary of State designated catchments as sensitive to Nitrogen and/or Phosphorus. The announcement will require the upgrade of wastewater treatment works within the nutrient sensitive catchment unless they are designated as exempt from this requirement or added to the list for upgrade. The Secretary of State has indicated that the exemption process will be complete by 1 April 2024. This will give clarity on the nutrient loading arising from development proposals.

Information regarding specific catchments

Updated nutrient calculators

Following the announcement by DEFRA on 25 January 2024, Natural England have released updated nutrient calculators for the following catchments:

  • Poole Harbour;
  • Somerset Levels and Moors;
  • River Avon; and
  • River Axe.

DEFRA are currently undertaking an exemptions process which will be completed by 1 April 2024. This process may add to or remove additional wastewater treatment works form the requirement for upgrade and as such, these calculators form an interim position. A further update will be made in due course, following the exemptions process.

Poole Harbour

Our dedicated page for nutrient neutrality in Poole Harbour has information relating to Nutrient Neutrality in this catchment, including the latest update from Natural England in their letter of 26 August 2022.

Somerset Levels and Moors

The Somerset Phosphate Budget Calculator (March 2024) should be used to calculate nutrient loads. All developments will need to demonstrate nutrient neutrality for Phosphorus. Somerset provide step by step guidance on the use of this calculator on their webpages.

River Avon

The updated (February 2024) nutrient budget calculator should be used to calculate phosphorus loads. All developments will need to demonstrate nutrient neutrality for Phosphorus using these tools:

Chesil and The Fleet

The Natural England Chesil and The Fleet nutrient budget calculator (February 2024) should be used to calculate nutrient loads. All developments will need to demonstrate nutrient neutrality for Phosphorus and Nitrogen using these tools:

River Axe

The updated (February 2024) nutrient budget calculator should be used to calculate Phosphorus loads. All developments will need to demonstrate nutrient neutrality for Phosphorus using these tools:

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