Nutrient Neutrality Calculator
Enter your postcode to check your catchment and get an indicative nutrient budget. Covers all 27 Natural England catchments with real WWTW data.
1 Enter your site postcode
Good news — nutrient neutrality doesn't apply here
Your postcode is not within any of the 27 Natural England nutrient neutrality catchments. This means nutrient neutrality requirements should not affect your planning application.
If you think this might be wrong (e.g. your site is near a catchment boundary), get in touch and we can check manually.
Ask us to check2 Your catchment
Development details
3 Your indicative nutrient budget
This is an indicative screening figure based on catchment-median WWTW concentrations. A full nutrient budget for planning requires site-specific WWTW data, detailed land use analysis, and an approved mitigation strategy.
Get a Full Nutrient Budget Report
Our environmental consultants prepare planning-ready nutrient budgets for all 27 catchments. Includes WWTW-specific data, land use analysis, and mitigation strategy.
Get a QuoteOr call us on 020 8156 6076 for a free consultation.
Nutrient neutrality is a hard constraint in 27 catchments across England.
Where new development could increase nitrogen or phosphorus loads to internationally protected habitats (SACs, SPAs, Ramsar sites), planning authorities must be satisfied that the development will be nutrient neutral. This often requires a detailed nutrient budget prepared by a qualified environmental consultant.
This calculator uses Natural England's published WWTW data (NECR459) to give you an early-stage budget across all 27 catchments currently in force.
Catchments covered
- Solent (78 WWTWs)
- Somerset Levels (111 WWTWs)
- River Eden, Teesmouth, The Broads
- Poole Harbour, River Avon, River Itchen
- 22 further NE-designated catchments
From postcode to nutrient budget in under a minute.
Enter your site postcode
The tool identifies which catchment your site falls within — or confirms you're outside a nutrient neutrality zone.
Enter development details
Number of dwellings and expected occupancy date. The tool selects the appropriate WWTW concentrations for your catchment and timeline.
Review your nutrient budget
See your indicative nitrogen and/or phosphorus load with a full formula breakdown and plain-English interpretation.
Get the full report
Request a full planning-ready nutrient budget from Aegaea's environmental team — delivered in 5 working days.
From calculator to planning-ready evidence.
This tool gives you an early-stage indicative budget. For planning submission, you need a full nutrient budget report prepared and signed off by a qualified environmental consultant, with catchment-specific WWTW apportionment and an approved mitigation strategy.
Aegaea prepares nutrient budgets for all 27 catchments. We can also source and arrange mitigation credits where required.
Full nutrient neutrality services
- Catchment screening and nutrient budgeting
- Planning-ready technical report
- Mitigation strategy and credit sourcing
- Liaison with Natural England
Frequently asked questions
- What is nutrient neutrality?
- Nutrient neutrality means new development must not increase nitrogen or phosphorus loads to internationally protected water habitats (SACs, SPAs, Ramsar sites). Where it applies, you need a nutrient budget showing your development is neutral — or you need to purchase mitigation credits.
- How do I know if my site is in a nutrient neutrality catchment?
- Enter your postcode in the tool above. It checks your local authority against Natural England's 27 designated catchments and tells you instantly whether nutrient neutrality applies to your site.
- What data does this calculator use?
- The calculator uses median wastewater treatment works (WWTW) concentrations extracted from Natural England's published NECR459 nutrient calculators. It applies the standard formula: dwellings x occupancy x water usage x 365 / 1,000,000 x concentration, with a 20% precautionary buffer.
- Is this calculator accurate enough for planning?
- This tool provides an indicative screening budget. For planning submission, you need a full nutrient budget report using your site's specific WWTW, land use data, and an approved mitigation strategy. The indicative figure is typically within 10-20% of the full calculation for standard residential schemes.
- What is the 20% precautionary buffer?
- Natural England's methodology (NECR459) requires a 20% uplift on the calculated nutrient load as a precautionary buffer. This accounts for uncertainty in the data and ensures the development achieves genuine nutrient neutrality.
- My site needs both nitrogen and phosphorus — is that common?
- Yes. Catchments like Stodmarsh (Kent), The Broads (Norfolk), and Chesil and the Fleet (Dorset) require budgets for both nutrients. The calculator automatically checks both where required.