Nutrient Neutrality Statements & Assessments

In nutrient vulnerable areas, you now may need a nutrient neutrality statement to accompany a planning application. Any development that will increase nutrient load may require assessment of nutrient load and planning of mitigation of any increases.

Aegaea have been working across multiple regions reviewing Nutrient Neutrality requirements, so get in touch today to see how we can support your development.

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What is Nutrient Neutrality?

In March 2022, Natural England published advice that stated “Any net increase in overnight accommodation will need to ensure the nutrient impact is considered and addressed where appropriate. This includes developments that propose to connect to the mains or off grid treatment works, such as package treatment plants (PTPs), or composting toilets”.

Where does Nutrient Neutrality Apply?

We’ve compiled a list of regions affected by the new guidance in our FAQs below, or check out our handy map to see whether your site location is within a Nutrient Neutrality affected area. Just search for your postcode or location in the map – if it shows up covered by a green polygon, you might need Nutrient Neutrality. In which case, just give us an email or a call!


How is Nutrient Neutrality Implemented?

Development plans can be considered ‘nutrient neutral’ where they can demonstrate that they will cause no overall increase in nutrient pollution affecting specified Habitats Sites. As such a nutrient neutrality calculation and offset plan must be completed by impacted developments.  This must take into account:

  • The nature of the existing site, including land use
  • The nature of the proposed development including occupancy land use and treatment provision.

This means that, understanding your development and how it impacts and changes the existing land use will have a big impact on the potential requirement for Nutrient Budget mitigation and management.


How do you achieve Nutrient Neutrality?

Developers are likely to have to include offsets, such as

  • on-site measures such as Sustainable Urban Drainage Systems (Suds) which can also be retrofitted into existing developments
  • agricultural land use change (e.g., intensive agriculture to woodland)
  • treatment wetlands (Wastewater Treatment Works, Package Treatment Plants)
  • interceptor Wetlands (agricultural run-off)
  • replacement of inefficient Package Treatment Plants/Septic Tanks
  • Nutrient Trading (currently only in Somerset and Solent regions)

This may restrict your development size or lead to increased cost for mitigation and planning, but whatever the mitigation, it needs to be suitably located to remove the effect of new development – within the same catchment as the development; upstream of the Habitats site and / or the development (source:

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Data and Calculations for Nutrient Neutrality

The assessment for Nutrient Neutrality is quite data intensive, we will need to include the following:

  • intended discharge receptor (Waste Water Treatment Works)
  • Rainfall data
  • Soil Types
  • Red Line Boundary Area
  • Land Available for mitigation within the proposed area
  • Budget for offset trading or mitigation (only in Somerset and Solent as of 2022).

An assessment of the nutrient budget will be assessed in four stages, in line with the national guidance, resulting in a total nutrient load requiring offset. 

Calculation of Nutrient Budget

To achieve nutrient neutrality, a nutrient budget is calculated using quantities of nitrogen (N) generated by a development. Measured N concentrations vary according to exactly what is measured and “the key measurement is Total Nitrogen (TN), i.e., both organic and inorganic forms of nitrogen, because this is what is available for plant growth.”

TN is the sum of:

  • the inorganic forms – nitrate-nitrogen (NO3-N);
  • nitrite-nitrogen (NO2-N);
  • ammoniacal – N; and
  • organically bonded nitrogen

The Advice confirms that at the HRA (Habitats Regulation Assessment) ‘appropriate assessment’ stage “a nutrient budget [should be] calculated according to this methodology and demonstrating nutrient neutrality is, in our view, able to provide sufficient and reasonable certainty that the development does not adversely affect the integrity, by means of impacts from nutrients, on the relevant internationally designated sites.”



This four stage process gives a total Nutrient Load that will require mitigation to pass the Natural England guidance.  We work with your drainage team to help plan the appropriate mitigation strategy and can liaise with the Local Authority to help acceptance of the mitigation proposals. The legislation and guidance is very recent, so a number of Local Authorities will be reviewing these assessments for the first time. As such, plan ahead to leave enough time to get these right!

Nutrient neutrality is here to stay, it is important to get expert advice!

Frequently Asked Questions

If you are within any of the following Local Authority Regions, or specific areas and you are increasing the amount of “overnight accommodation”, then you might need to undertake Nutrient Neutrality – you can also see these regions in our handy map!

​Ashford Borough Council, Basingstoke and Deane Borough Council, Bournemouth, Christchurch and Poole Council, Canterbury City Council, Chichester District Council, Cornwall Council, Dorset Council, Dover District Council, East Hampshire District Council, Eastleigh Borough Council, Exmoor National Park Authority Fareham Borough Council, Folkestone and Hythe District Council, Gosport Borough Council, Havant Borough Council, Herefordshire Council, Isle of Wight Council, Malvern Hills District Council, Maidstone Borough Council, Mendip District Council, Mid Devon District Council, New Forest District Council, New Forest National Park Authority, Portsmouth City Council, Sedgemoor District Council, Somerset West & Taunton Council, South Downs National Park Authority, South Somerset District Council Southampton City Council, Swale Borough Council, Test Valley Borough Council Wiltshire Council, Winchester City Council, Allerdale Borough Council, Borough Council of King’s Lynn and West Norfolk, Breckland Council, Broadland & South Norfolk Council, Carlisle City Council, Cheshire East Council, Cheshire West and Chester Council, Copeland Borough Council, Darlington Borough Council, Derbyshire Dales District Council, Durham County Council, East Devon District Council, East Riding of Yorkshire Council, East Staffordshire Borough Council Eden District Council, Great Yarmouth Borough Council Hambleton District Council, Hartlepool Borough Council, High Peak Borough Council, Hinckley and Bosworth Borough Council, Lake District National Park Lichfield District Council, Middlesbrough Council, North Norfolk District Council North Warwickshire Borough Council, North West Leicestershire District Council, North York Moors National Park Authority, Northumberland County Council, Northumberland National Park Authority, Norwich City Council, Peak District National Park Authority, Redcar and Cleveland Borough Council, Richmondshire District Council, Shropshire Council, South Derbyshire District Council, South Lakeland Council, Stockton-on-Tees Borough Council, Swindon Borough Council, The Broads Authority, Vale of White Horse District Council, West Berkshire Council.

Not exactly. At the moment, unless you are able to access the pilot trading program in Solent and Somerset authorities, then yes, you have to provide mitigation within the same river catchment as your development.

  • One natural solution is constructed Wetlands. They have been shown to be an ­efficient way to remove nutrients and pesticides from runoff. Constructed appropriately and put in place in a sensible place, they can remove significant amounts of nutrients, while helping restore natural habitat and contributing to reduced flooding.­ This may not be sufficient, depending on the nutrient load that needs to be removed, so they can be combined wiht other engineering solutions, such as activated sludge, or effluent being treated through a trickling filtrate. With nitrate removal becoming and increasing global concern to combat eutrophication of watercourses, these techniques are evolving swiftly.

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