Water Neutrality Statements

Aegaea have been working on water neutrality statements for residential and industrial developers in affected regions since 2021. We have successfully delivered water neutrality requirements in affected regions, unlocking development potential for clients.

Our expertise is helping you unlock the development potential of your site, no matter what the size – from house extensions to 5000+ units, Aegaea works alongside you every step of the way.

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What is Water Neutrality as it relates to development?

The definition of water neutrality is the use of water in the supply area before the development is the same or lower after the development is in place.
New development must not add to this negative impact. This means that development where it is located within the Sussex North Water Supply Zone, will have to demonstrate that it will not increase pressure on water resources. This can be achieved by making development “water neutral”, where for every new development, total water use in the region after the development must be equal to or less than the total water-use in the region before the new development.

Why do water neutrality areas exist?

The increasing demand for water is thought to be harming internationally protected species, with the potential threat of extinction for some of these species. In response to this, Natural England has advised that new developments within this zone, which affects Horsham, Crawley and part of Chichester District (including some parts of the South Downs National Park) must not add to this impact. The area is served by supplies from a groundwater abstraction at Pulborough. This has the potential to impact upon the Arun Valley, a Special Area Conservation (SAC), Special Protection Area (SPA) and Ramsar site. The council and other affected authorities continue to work together to further our collective understanding of the issue.

Natural England there cannot, with certainty, conclude that the Sussex North Water Resource Zone, that includes supplies from groundwater abstraction, is not having an adverse effect on the integrity of:

  • Arun Valley Special Area Conservation (SAC);
  • Arun Valley Special Protection Area (SPA); and
  • Arun Valley Ramsar Site.

The Sussex North Water Resource Zone impacts;

  • Horsham
  • Crawley
  • Part of Chichester (including some parts of the South Downs National Park)

In September 2021, Natural England issued substantive advice for all applications which fall within Sussex North’s Water supply zone.

As it cannot be concluded that the existing abstraction within Sussex North Water Supply Zone is not having an impact on the Arun Valley site, we advise that developments within this zone must not add to this impact. This is required by recent caselaw, Case C-323/17 People over wind and Sweetman. Ruling of CJEU (often referred to as sweetman II) and Coöperatie Mobilisation for the Environment and Vereniging Leefmilieu Case C-293/17 (often referred to as the Dutch Nitrogen cases).

Developments within Sussex North must therefore must not add to this impact and one way of achieving this is to demonstrate water neutrality.

Am I in a Water Neutrality Zone?

To discover if you are affected the link below is provided to postcode search and show if you are affected.

View map of Sussex North Water Resource Zone on the West Sussex County Council website (opens in new window)

Since 2021 Aegaea has been working with residential and industrial developers to meet Water Neutrality Requirements. Talk to us today!

Are there any exemptions for Water Neutrality requirements?

Supply of Water

If development is not supplied by the abstractions in Sussex North Water Supply Zone, then there would be no need to demonstrate water neutrality. The applicant will, however, need to evidence where the supply to their site comes from and obtain Southern Water’s agreement that the supply is sourced from outside the supply zone


Horsham guidance states that the planning authority has screened out all householder planning applications (with the exception of those proposals for annex accommodation and swimming pools), and all development granted under Schedule 2 Parts 1 and 2 of the General Permitted Development Order from having a likely significant impact on the Arun Valley, as there is no evidence that extensions or minor alterations to dwellings will directly result in an increase in water consumption.


  • Householder Applications (excluding annexes and swimming pools) including those defined under Schedule 2, Part 1 of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended)
  • Applications for Advertisement Consent
  • Applications for Tree Works
  • Full and Prior Approval applications for Telecommunications Infrastructure, including those defined under Schedule 2, Part 16 of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended)
  • Minor developments where there is no water usage (e.g. surface car parks/hardstanding, vehicular crossovers, shopfronts, recladding)
  • Applications for Development comprising Minor Operations as defined under Schedule 2, Part 2 of the Town and Country Planning (General Permitted Development) (England) Order 2015 (as amended)
  • Applications for Non-Material Amendments involving no increased water usage.


Guidance for exemptions is not shared on the Chichester council website, it is however viewed that the guidance for exemptions would emulate that of Horsham and Crawley. Please contact us for more information and the latest positions.

Im in a Water Neutrality Zone, what next?

Mitigation options can exist to meet the requirement of the Natural England Statement and the local plan policies of the affected Local Planning Authorities (Crawley, Chichester and Horsham). Baseline and proposed water calculators are required to understand the demand for water and the differences between each. Once the demands are known we can then review options best required to achieve Water Neutrality for each development.
Of the options available these are summarised below;

For new developments where the consumption will be greater than 20m3 per day an abstraction licence is required. The abstraction license can take longer to achieve however it gives the assurance of a protected supply and the licensing process provides the assurances Natural England (NE) need to approve the scheme.

For developments using less than 20m3 per day no licence is required. The option of adopting a borehole (licensed or unlicensed) does require a hydrogeology report or equivalent.

For either option, groundwater quality must be addressed and is regulated by the Council through the Private Water Supplies (England) Regulations 2016 (as amended). The quality assessment should consider the risks of pollution to the new drinking water supply and the properties of the underlying soils and rock. As well as the Hydrogeology report which will cover groundwater resources, hydrogeological links between aquifer units; impacts on nearby SSSI’s and their impact zones, or any other ecological features; and

Should the options of boreholes not be viable or preferred the other option is for the ability to purchase water credits from public and private bodies.
Another alternative is to source property/uses of water in the affected Sussex North Area that could provide credit through retrofit or replacement of existing water demand assets with more efficient assets.
This could even include property you own in the affected zone. Credits can only be achieved by working through WAT 1 BREEAM calculations (commercial development) or Part G Building Regulations (residential).
It should be noted that property in Chichester cannot be used to provide credit for a development in Horsham. Credit and mitigation options are limited by each local planning authority boundary.

Water Neutrality Case studies

Residential Development

The client proposed to build a 1-bedroom self-contained annex, separate to the main dwelling to house elderly relatives. As part of the planning permission a Water Neutrality Statement was requested by Horsham District Council the Local Planning Authority (LPA). To achieve water neutrality, it was required to offset the water demand of the new dwelling (annex) by retrofitting the existing dwelling with water efficient fittings and to install rainwater harvesting on the new dwelling (annex) to supply the WC and washing machine along with water efficient fittings.

Rainwater harvesting

Calculations in accordance with Part G were undertaken for the existing dwelling (before and after retrofit) and the new dwelling.

Rainwater collection and rainwater storage calculations were produced in accordance with the appropriate Standards along with an overview of the rainwater harvesting system including maintenance. The development was approved.


Commercial Development

Aegaea supported a large industrial complex, which had several warehouses and factories. Our client sought planning permission to erect two new factories and a warehouse, one of the respective conditions was to provide a Water Neutrality Statement.

Through collaboration with the client to find an appropriate solution that best fit their operations and budget, a solution was found. The solution appeased both the LPA and client on this occasion the solution required retrofitting of existing fittings to reduce flow in existing factories. Previous solutions considered was to incorporate rainwater harvesting but this was discounted as it would have required a large capital cost for the tank, excavation, and supporting build + infrastructure. Our experts believe in adopting a systematic approach to find a solution that meets the requirements of planning and the client with focus to implementation and operation.

Speak to a Water Neutrality expert about your development

Daniel Cook
I’m a Chartered Water and Environment Manager and specialist Flood Risk Consultant, working in the environmental consultancy sector since 2011. Specialist Subject: flood risk policy!
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