The Basics of Nutrient Neutrality…

The hot topic in planning at the moment is Nutrient Neutrality due to the recent advice issued by Natural England which has the potential to halt developments within areas identified.

Whilst not a new issue, the guidance has been updated and the number of areas covered increased.  We’ve had numerous calls from clients and people in the industry asking about the advice and what the implications area, so we’ve published this article to hopefully cover the basics.

What is the Nutrient Neutrality Advice published by Natural England?

Natural England have issued advice regarding certain areas identified by them which have unfavourable conservation status (see below for a list & map) where development will result in additional nutrient loads that may have an adverse effect.  The current advice associated with these areas is likely to cause significant delays to countless planning applications.

The advice seeks to ensure that planning applications and plans affecting habitats sites in ‘unfavourable conditions’ should be carefully considered and mitigation should be in secured to ensure there are no adverse effects in order to meet the requirements of the Conservation of Species and Habitats Regulations 2017 (as amended).

In short development that is not nutrient neutral in these areas will not be supported.

This FLOWCHART should help developers with the steps in Nutrients Assessment Methodology for Development.

What’s the problem with Additional Nutrients?

Nutrient pollution is a big environmental issue for our water ecosystem. In freshwater habitats and estuaries, increased levels of nutrients (especially nitrogen and phosphorus) can speed up the growth of certain plants, impacting wildlife. This is called ‘eutrophication’ and it is damaging protected sites. As such, some sites are classified as being in ‘unfavourable condition’.

The sources of nutrients generally include sewage treatment works, septic tanks, livestock, arable farming and industrial processes. Where sites are already in unfavourable (poor) condition, extra wastewater from new housing developments can make matters worse.

By designing development alongside suitable mitigation measures, additional damage can often be avoided. This approach is called ‘nutrient neutrality’. It essentially allows developments to progress without impacting on the condition of the important wildlife and/or protected sites.

What are the Nutrient Neutrality Areas?

This is not a new issue; however, the amount of catchment areas has increased in March 2022. The most recent advice issued by Natural England increases the 32 Local Planning Authorities (LPAs) already affected by nutrient pollution with 42 new LPAs added to the list.

The advice applies to a catchment area (not the Council), so whilst a Council maybe named below the advice may not cover the entire administrative area:

What development types are affected by the advice?

Nutrient neutrality is required for overnight accommodation including new homes, student accommodation, care homes, tourism attractions and accommodation. The nutrient neutrality approach applies to proposals for a net increase in dwellings. Replacement dwellings are generally excluded.

So, is it just Residential Development?

The advice relates to any overnight accommodation, campsites, glamping pods, holiday lets, shepherd’s huts etc are all included. This includes developments that propose to connect to the mains, off grid treatment works or composting toilets.

Other development not involving overnight accommodation is generally not included, so the advice does not apply to new schools, shops/retail development, offices etc.  This is on the basis that the people using the commercial developments are likely to be living in the catchment area and the wastewater generated will be included in any calculations from additional residential units and accommodation.

However, be aware that other applications will be considered on their individual merits.  For example, infrastructure that supports agricultural intensification, such as new or expanded livestock housing, or new or enlarged slurry storage may be included, as may Anaerobic Digester (AD) plants, which require the input of organic matters often in the form of farmyard manure and/or arable plant matter.

What about Approved Planning Applications, Discharge of Conditions Applications or Prior Approvals?

The advice relates to new projects and plans which have not yet had a decision, for instance a competent authority (the LPA or Secretary of State) may only approve a plan or project where they are sure it will not adversely affect the integrity of a protected site.  If there is doubt planning permission cannot be granted.  This applies to planning applications and prior approval process where they involve a development for overnight accommodation.

This advice also applies to planning applications at the reserved matters approval stage of the planning application process, and to applications for prior approvals and/or certificates of lawfulness for a proposed use or operation.

There is no reference in the advice (or any document associated with the advice) which states that the new requirements for nutrient neutrality can be retrospectively applied to unimplemented permission.  However for permissions which have been approved subject to conditions where the conditions have yet to be discharged.  The High Court has decided that government rules aiming to mitigate the impact of nutrient pollution on protected waterways apply to the discharge of planning conditions as well as the earlier permission stage and that the legal basis of the requirements in European Union law still stands despite Brexit.**

How do you calculate nutrients for a site?

There is National Generic Methodology within the Nutrient Neutrality advice with associated new nutrient catchment calculators. This approach will affect existing assessments that pre-date its introduction. Below are the links to the various documents/calculators which developers need to be aware of:

Natural England have previously advised that those undertaking the assessment should do so using a precautionary approach when addressing uncertainty and calculating nutrient budgets.

What happens if there is an increase in nutrients associated with a development?

If the nutrient calculation results in an increase in nutrients associated with a project, mitigation will be necessary to achieve nutrient neutrality.

What is Mitigation?

Mitigation means action taken to stop nutrient pollution impacting protected sites. This could be onsite – preventing nutrient pollution directly from the development in question, or offsite – reducing nutrients from other sources that affect the protected site overall.

Mitigation ideally should be addressed locally and could include the upgrading of sewage treatment works, creating interceptor wetlands or taking land that generates excess nutrients out of use, for example converting intensively farmed land to open space provision.

Natural England are developing a framework for assessing the effectiveness of habitat restoration mitigation and an associated reference tool. The results are expected shortly, and will be developed into guidance on best practice for the use of nature-based solutions to mitigate nutrient pollution.  But what else?

  • Ofwat is developing a proposal that could enable water companies to directly accept developer contributions for improvements to wastewater treatment works as a means of mitigating nutrient loads from new developments.
  • DEFRA are piloting nutrient trading schemes with EnTrade in the Solent and in Somerset this year and will use this learning to inform next steps. Through the Natural Environment Investment Readiness Fund, DEFRA have funded 13 projects that explore water quality issues, including nutrient management and credit trading. The results of the pilots and lessons learned from the fund will allow DEFRA to determine how they could support the creation of nutrient markets in each catchment in the future.
  • Local Authorities in Kent, Somerset and the Solent have already paved the way in creating ‘nature-based solutions’ by buying land to create wetlands, allowing planning permissions to be granted.

Where measures intended to avoid or reduce the harmful effects of development upon a European site are proposed, such measures can only be taken into account at the Appropriate Assessment stage of Habitats Regulation Assessment.

However, be aware that there are a number of situations where a nutrient neutral approach may not be an appropriate mitigation measure (see the relevant section below for details).

What are the Planning Implication?

Planning Applications:

In a nutshell Natural England declaring a catchment area to be in an “unfavourable condition” from Nitrate or Phosphate pollution is going to in general slow down development and the processing of planning applications. In the short term it seems the areas affected are halting issuing decisions on effected applications until further clarity is gained on appropriate mitigation.

Any proposed development, in relevant Local Planning Authority areas, which is likely to increase nutrient loading, directly or indirectly, will need to be assessed according to applicable legislation.

For planning applications currently being considered by a LPA (even those which have been minded to approve) further information may be requested and Natural England and others re-consulted.  This HRA FLOW DIAGRAM summarises the key stages in the Habitats Regulation Assessment (HRA) process and the questions which need to be answered in relation to the habitats site and the proposed development at the screening and the appropriate assessment stages.

Local Plans

There is already an obligation on the plan making authority in relation to the Habitats Regulations. It is assumed that given the process for consultation with various statutory bodies that the nutrient neutrality advice will be absorbed into the preparation process for plans.  However, some sites which may have been considered suitable for development previously may now be in ‘unfavourable condition’ and alternative sites may need to be considered – unless mitigation can be included during the plan making stage.  This could mean delays in the Local Plan process to assess sites, find appropriate mitigation and re-consult various parties.

For Developers:

Under this advice, developments are more likely require Habitats Regulations Assessments in catchment areas. Where developments would fail the requirements of the Appropriate Assessment, developers may be asked to take action to mitigate impacts through nutrient neutrality such as:

  • building additional mitigation into their plans onsite,
  • working with the LPA to arrange for mitigation offsite, or
  • purchasing nutrient credits via a nutrient trading scheme (where other landowners in the catchment have taken action to reduce their nutrient load).

Delivering ‘nutrient neutrality’ under the Habitats Regulations may impose additional costs on development and the process will certainly add delays to the process.

Housing Supply:

If there is a stalled development process, it’s likely we’re going to see housing land supplies reduce, and should this be the case potentially we’ll see more LPAs have a sub-5year supply of land for housing meaning that the presumption in favour of sustainable development will bite.


Potentially we could see a decline in farming due to the possibility of ceasing intensive farming in favour of open space to mitigate for a development. This is not good for the British farming industry and could see a reliance on more imported food.

Are there any situations where Nutrient Neutrality may not be an appropriate mitigation measure?

For Lake or wetland sites and particularly those with long residence times or which have a limited or no outflow nutrients will accumulate over time and therefore they are particularly vulnerable to even small increases in nutrients which will further hinder restoration. Where one of these sites is already unfavourable due to nutrient enrichment it is also likely that current sources of nutrients will need to be reduced to restore the site and therefore using these measures for nutrient neutrality would undermine the ability to restore the site.

  • Where the development impact is direct to a habitats site terrestrial wetland habitat rather than to surface water. In these circumstances the mitigation would need to be at the exact same location where the development is having its effect on the site, as reductions in nutrients in other locations of the wetland would not neutralise the effect of the development. Therefore, potential mitigation options will likely be very limited.
  • Where the development impact is via groundwater discharging direct to a habitats site terrestrial wetland habitat rather than to groundwater discharging to surface water. In these circumstances there will be variation in the effectiveness of measures depending on their location within the groundwater catchment compared to development. This means measures may need to be located in the same part of the groundwater catchment to ensure that it would neutralise the nutrient increase from the development before it reaches the site, thereby constraining the area where mitigation could be targeted to a smaller area.
  • Development (particularly larger developments) in the headwaters of a catchment. In these circumstances the area upstream of the development where nutrient neutrality mitigation can be located will be restricted to a small area, providing much more limited and perhaps in some cases no feasible opportunities for mitigation through nutrient neutrality, although other mitigation measures may be possible.
  • Habitats sites with small catchments. Again, there will be a much more limited area where mitigation can be targeted thereby limiting potential nutrient neutrality mitigation opportunities.
  • Where widespread and/or large-scale uptake of measures are needed to restore the habitats site or part of the site thereby significantly constraining the measures available for counterbalancing additional nutrient inputs in a way which will not undermine site restoration.


From a development perspective the process of securing planning permission has just become harder for the types of developments which are mentioned above and are within the areas defined by Natural England as being in an unfavourable condition.  The advice is relatively new to many authorities and so in the short terms we anticipate a halt on issuing decisions where the advice would be relevant.

Processing applications is going to become even more protracted with the additional assessments required and consultations necessary.

Finding appropriate mitigation is going to be difficult for some types of development, protracted in terms of securing it and for others not possible to mitigate.  Ultimately things are going to become more expensive and uncertain for developers in the short term.

Our advice make friends with Ecologists and Engineers as they are going to play an important role in wading through this process!

Related Content

The Government have announced a series of practical, financial, and legislative measure to help address the issue of nutrient neutrality in affected areas across the UK.

In addition to Natural England’s advice, a Written Ministerial Statement ‘Delivering the Environment Act: taking action to protect and restore nature’, a Defra policy paper ‘Nutrient Pollution: reducing the impact on protected sites’ and a letter from the Chief Planner ‘Nutrient Pollution: Neutrality, Support and Funding’ were also published in March 2022

The conservation of Habitats and Species Regulations 2017 (as amended) legislation protects important water dependant places (lakes, rivers, estuaries etc).  And in accordance with legislation, a Habitats Regulations Assessment (HRA) is needed for plans and projects that are likely to have a significant effect on protected sites.


*Please be aware that this advice is recent therefore interpretation of this advice may change when more details, practice guides etc are produced.

**C.G.Fry & Son Limited v Secretary of State for Levelling Up, Housing and Communities. Case Number: CO/12/2023