Nutrient Neutrality

About Nutrient Neutrality

Alongside all other local planning authorities in Norfolk, the council received a letter dated the 16th of March 2022 from Natural England concerning nutrient pollution in the protected habitats of the River Wensum Special Area of Conservation and the Broads Special Area of Conservation and Ramsar site. The letter advised that new development within, or draining into, the catchment of these habitats comprising overnight accommodation, or any development not involving overnight accommodation but which may have non-sewerage water quality implications, has the potential to cause adverse impacts with regard to nutrient pollution. Such development includes, but is not limited to:

  • New homes
  • Student accommodation
  • Care homes
  • Tourism attractions
  • Tourist accommodation
  • Permitted development (which gives rise to new overnight accommodation) under the Town and Country Planning (General Permitted Development) (England) Order 2015
  • Any development not involving overnight accommodation, but which may have non-sewerage water quality implications.

The Conservation of Species and Habitats Regulations 2017 require local planning authorities to ensure that new development does not cause adverse impacts to the integrity of protected habitats such as the River Wensum or the Broads prior to granting planning permission. 

The council has worked closely with its neighbouring authorities, as well as with Natural England and Anglian Water, to provide a platform which will enable developers to buy credits to mitigate for the impact of nutrients.  Any mitigation that releases credits needs to be in place before any dwellings are occupied, and be in place for at least 80 years.

Advice to Applicants and Agents

First, it is important to identify whether your development lies inside or outside the River Wensum or the Broads Special Area of Conservation (SAC). If you are finding it difficult to identify whether you are inside or outside a catchment area, then please contact your case officer who will be able to advise.

Please note the maps shown on our website are the only maps we are able to provide. However, we have been informed by Natural England that more detailed maps can be accessed on Defra's Interactive Mapping System, MAGIC (opens new window). This system has been updated with an SSSI Impact Risk Zones layer, which can be used to identify whether a location is within a nutrient impact area.

    If you are inside a Catchment Area:

    First, check whether your planning application site lies in a Nutrient Neutrality Catchment Area.

    View the Nutrient Neutrality map (opens new window)

    If you lie in an affected catchment area then you will need to undertake the following actions:

    1. Within 10 days of receipt of a valid planning application, write to your case officer agreeing to an extension of time for a period of 6 months from the date of this letter.  Please note failure to agree to an extension of time may result in refusal of planning permission.
    2. Run the Norfolk or Natural England (NE) Nutrient Budget Calculator (if you use the NE calculator and you fall within both the Broads SAC and the Wensum SAC then you only need to run the Broads SAC calculator).  This must be completed within 3 weeks of submission of the planning application or your application may be refused.
    3. Carry out a shadow Habitats Regulations Assessment (HRA) and provide to the case officer, as soon as possible.
    4. Identify appropriate mitigation, if possible.

    At present there are credits available in the Yare catchment only.  To purchase or find out more information, please visit theNorfolk Environmental Credits website (opens new window)If you wish to purchase credits it is essential to register your interest on theNorfolk Environmental Credits 'buying' website (opens new window). For development located within the other catchments, work is ongoing looking for solutions and mitigation, so it is worth checking the Norfolk Environmental Credits website regularly for updates.

    If you identify your own mitigation, which is encouraged, the Local Planning Authority will, as the competent authority, then carry out an Appropriate Assessment (AA), and permission for the plan or project may only be given if the AA allows us to be certain that your development will not have an adverse impact on the integrity of the SAC i.e. where no reasonable scientific doubt remains as to the absence of effects.

    Atraining video (opens new window) is also available, which provides a step-by-step guide on how to use the Norfolk nutrient calculator.

    Sites outside the SAC Catchment Area(s)

    Please note if you lie outside the Nutrient Neutrality Catchment Areas but are close to them, you may be asked to provide more information and agree to an extension of time, as set out above.

    Enforcement Action

    Finally, please be aware that this does affect all parts of the planning application process (Full, Outline, Reserved Matters, Variations (s.73) whereby additional overnight stays or units are created and pre-commencement drainage Discharge of Condition Applications). Therefore, you are advised not to start work on any planning permission prior to all the necessary permissions being in place, including discharging any drainage conditions. Works commenced unlawfully which result in significant environmental effects (which the guidance says are inevitable if development is within or drains into the Catchment(s)) will result in appropriate enforcement action.

    Nutrient Neutrality: Which Calculator Should I Use?

    The Norfolk nutrient budget calculator is now available.  You can use it for proposed developments in the Norfolk catchments impacted by Nutrient Neutrality. It provides a rapid calculation of net phosphate and nitrate loadings from developments based on local data.  This includes phosphate and nitrate offsetting calculations for on and off site locations. It can now be used to inform planning applications with regards to NN.

    Developments can either use this calculator or the Natural England calculator to find out the nutrient level for your proposal.  If you are located within one of the SAC Catchments or foul drain into one of those Catchments, you will need to submit one or both of the completed calculators in support of your planning application. Your planning application will only be able to proceed if:

    • the proposed development is nutrient neutral; or
    • you have identified appropriate mitigation (to make it neutral) that can be secured and delivered.

    With regards to which calculator to choose, the Norfolk specific calculator uses local data to provide an accurate nutrient calculation.  The Natural England calculator is already approved by NE but takes a national approach to NN and does not allow for local relevant data to be taken into consideration.  It will be up to the individual developments to decide which calculator (or both) they decide to use.

    To help, the Norfolk calculator contains a help section to assist with the stages of the process and the video provides a step by step guide on how to use the calculator.

    Natural England Comments

    Natural England have provided written comments with regards to the Norfolk Calculator (PDF) [143KB] (opens new window) .

    The area of risk 

    New development in the Norfolk catchments impacted by Nutrient Neutrality may increase nutrient at the habitat sites identified by NE as being in poor condition. 

    View the Nutrient Neutrality Map (opens new window)

    The catchment area has a map of the applicable wastewater treatment works (WwTWs).  Please note:

    • That we cannot guarantee the accuracy of the WwTW data and you should contact Anglian Water for further information.
    • Developments within the catchment area that will drain to a WwTWs within the catchment will need to complete stages 1-3 of the calculator.
    • Developments located outside of the catchment area but that will connect to a WwTWs that drains to the catchment should not complete Stages 2 and 3.
    • Where a site is located within the hydrological catchment but drains to a WwTWs outside of the catchment then mitigation is not required.

    More help with the calculator

    If you need help to complete either calculator, we recommend using a specialist consultant.  Natural England also offer a Discretionary Advice Service which you could use.

    Student and communal accommodation

    For student and communal accommodation, it is recommended that you calculate average daily total water consumption for the development and enter this into stage one.

    Advice on Package Treatment Plants (PTPs)

    Addressing Phosphorus only for rural small-scale discharges (less than 2m3/day - typically less than approx. 5 dwellings) where there is no connection to mains foul.

    This relates to those sites in rural areas where there are no riparian routes to watercourses, where connection to mains foul drainage is not possible, where Package Treatment Plants or Septic tanks (small discharge up to 2m3/day directly to ground) are proposed, where specific criteria are met (see a - h below) and to assist in concluding no likely significant effects in respect of Nutrient Neutrality from Phosphorus only. Anyone seeking to utilise this methodology should be aware that this does not deal with Nitrates which will also need to be mitigated and HRA demonstrated.

    The Norfolk Authorities have commissioned a report (Royal Haskoning small scale discharges of Phosphorus: Low Risk Mapping) which follows and builds upon previously agreed interim guidelines between Natural England and Local Planning Authorities regarding small scale thresholds within the hydrological catchments of areas subject to nutrient neutrality guidance.

    The guidance relates to small discharges from Package Treatment Plants (PTPs) and Septic Tanks (STs) of less than 2m3/day directly to ground and it states that where all the requirements of pre-defined conditions are met, a PTP / ST will not have a likely significant effect on the designated site from phosphorus. The small-scale thresholds only apply to phosphorus and not nitrogen, which is a more mobile nutrient.

    Criteria a - h need to be satisfied for this approach for Phosphorous to apply.  Details of these conditions can be found at paragraph 2.2 of the report (link below)

    A small sewage discharge low risk zone map has been created to support the identification of areas where small scale discharges for Phosphorus may be acceptable.   The map defines the areas which fall within the low-risk zone where all the requirements of conditions a, b, c, d, e and g are met.

    Conditions f and h require site specific information and when provided alongside the mapping can be used to demonstrate that all the required conditions are met.

    Where all the conditions (a to h) are met then Natural England can advise that, in its view, a conclusion of no Likely Significant Effects alone and in combination for phosphorus can be reached in these circumstances.  However, nitrogen mitigation will still be required.

    For a PTP / ST to be accepted, it is expected that a technical report would need to be submitted which shows the location of the PTP / ST within the low-risk zone and any supporting evidence to demonstrate conditions f and h are met.

    The PTP / ST must also be able to achieve the appropriate Building Regulations requirements. The building regulations state that a connection to the foul sewer should be considered to be potentially feasible where the distance from the development site to the sewer is less than the number of properties multiplied by 30m. In addition to Planning Permission and Building Regulation approval, an Environmental Permit from the Environment Agency may also be required.

    Last updated: 23/11/2023 12:41:57