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Nutrient Neutrality: frequently asked questions (Professional) Development Management

Find answers to frequently asked questions and topics related to nutrient neutrality

How should LPAs deal with current and imminent planning applications in catchments affected?

Within the River Lambourn Nutrient Neutrality Zone, applications may be delayed to enable proposals to be screened in or out of the need for nutrient neutrality. Where a screened-in development type may give rise to additional nutrients within an affected catchment, either because the development is within an affected catchment boundary, or it drains into an affected catchment, it will be necessary to undertake a habitats regulations assessment, as per Natural England's advice.

The LPA, as a Competent Authority, should only grant permission if it is certain that the development will not adversely affect the habitats site. If adverse effects cannot be ruled out, it is likely that permission cannot be granted unless suitable mitigation is available.

Further work is currently underway to assess what mitigation is applicable and available to development within the River Lambourn Nutrient Neutrality Zone.

  • The calculator is not generally needed for householder applications, such as extensions (dependent on the size of the extension), if the LPA uses an average occupancy figure for new dwellings in the nutrient budget calculation, ie: 2.4 people per dwelling. This approach is in line with NE guidance and the calculators.
    However, consideration may need to be given to specific cases, such as changes to Houses of Multiple Occupancy.
  • Applicants for all new residential development that increases the floor space should use the River Lambourn Budget Calculator to see if their proposals result in an increase if phosphate pollution or not. This calculation should then be included in the planning application as part of the supporting evidence.


In general, commercial development, schools and retail can be exempted. This is because it is generally accepted that people tend to work and live in the same catchment, therefore wastewater is accounted for by the new housing.

In exceptional circumstances, ie: very significant commercial developments, nutrient neutrality may be needed.



Tourism accommodation is within the scope of the nutrient neutrality advice. Tourism infrastructure for day visitors should be included if there is clear evidence that people are travelling from outside the catchment.

Campsites operating on a 28-day basis should be included if they have wastewater infrastructure. Any impact would need to be pro rata to only 1 month, and the assessment would need to make a judgement as to whether the proposal would result in a likely significant effect.



Agricultural infrastructure and industrial applications should be considered on a case by-case basis due to the variation in nature and scale. Nutrient neutrality applies to agricultural developments that lead to an intensification of use.


Does the requirement to consider nutrient impacts affect reserved matters and discharge of conditions?

Natural England advises that the requirement to consider nutrient impacts applies to planning applications at the reserved matters approval stage of the planning application process, and to applications for grants of prior approval and/or certificates of lawfulness for a proposed use or operation.


What is the scope for Sustainable Urban Drainage systems (SUDs) to be secured through s.106 agreements?  

Such measures must be effective for the duration of the impacts. In the case of new housing the duration of the impact is typically taken as in perpetuity, with the costs of maintaining, monitoring and enforcing mitigation calculated for a minimum of 80 to 125 years.


How do the catchment boundaries provided by Natural England deal with the scenario where a development inside the catchment drains to a WwTW discharging out-with the catchment, and vice versa?

If a development is located within an affected catchment but is served by a wastewater treatment works that discharges outside of the sensitive catchment, the wastewater element of the proposed development can be excluded. The drainage of surface water will still need to be considered though.

If a development is located out-with an affected catchment but is served by a wastewater treatment works that discharges within the catchment, a habitats regulations assessment will be required. This also applies to surface water drainage.

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