Defra announced on 8 October 2025 that an agreement has been reached to unlock new home development in the Sussex North Water Supply Zone (SNWSZ). This move formally ends the four-year pause on development that was caused by water neutrality restrictions due to concerns over the amount of water being taken from rivers and wetlands in the Arun Valley.
A further announcement 31/10/2025 confirmed that Natural England will be withdrawing their position statement, thus ending the requirement for Water Neutrality Statements in planning. This decision, which NE communicated to local authorities, is the official trigger for the policy changes we are now seeing across the region.
The change is based on new evidence from Southern Water’s Hardham Basin Environmental Study (HBES). Natural England has confirmed that a new package of ecological measures and amendments to Southern Water’s abstraction licence (to be implemented by March 2026) will “decouple” new development from any potential impact on the Arun Valley.
As a result, NE has concluded that new development will not have a “likely significant effect” on the protected sites.
What this means for development in North Sussex
With the NE position statement gone, local authorities are no longer required to demand water neutrality. The focus has now decisively shifted from achieving neutrality to proving stringent water efficiency.
Water neutrality in Horsham
The council has removed its WNS requirements but is now requesting compliance with the 110 lpd standard. All applications for new housing will be required by condition to comply with the Building Regulations Part G Optional Technical Standard (currently 110 l/p/d) as required by Policy 37 of the Horsham District Planning Framework. https://www.horsham.gov.uk/planning/water-neutrality-in-horsham-district
Water neutrality in Chichester
Similar to Horsham, WNS has been removed, and the 110 lpd water efficiency standard is now the key requirement. As per Policy NE18 of the Chichester Local Plan 2021-2039, with water neutrality requirements having fallen away, the water efficiency standard for development will revert to 110 litres/person/day for residential or the minimum standards for BREEAM ‘Excellent’ within the Water category for non-domestic buildings.
https://www.chichester.gov.uk/water-neutrality-planning-applications
Water neutrality in Crawley
The council has confirmed that with the deletion of water neutrality, planning will revert to the 110 lpd standard. As per Strategic Policy SDC4 of the Crawley Borough Local Plan 2023-2040, with water neutrality requirements having fallen away, the water efficiency standard for development will revert to 110 litres/person/day for residential or the minimum standards for BREEAM ‘Excellent’ within the Water category for non-domestic buildings.
https://crawley.gov.uk/planning/planning-applications/you-apply/water-neutrality-crawley
Water neutrality in South Downs National Park (SDNP)
The South Downs National Park (SDNP) has also withdrawn its water neutrality requirement. However, developers must pay close attention to existing policy.
Policy SD48 remains in effect. This policy requires projects that increase a footprint by 100sqm or more to address water efficiency properly. This means that even without the overarching WNS, water remains a key consideration for projects within the park.
https://www.southdowns.gov.uk/water-neutrality-requirements-withdrawn/
For existing planning permissions with WNS conditions
If you have an existing permission that includes conditions or s106 obligations for water neutrality, councils will now consider applications under s.73 of the Town and Country Planning Act to remove those conditions. They will be replaced with the new, simpler condition requiring compliance with the 110 lpd standard.
For Current (Undetermined) Applications: You should contact your case officer immediately to discuss how you wish to proceed.
A key strategic note: If your application has already been heard by a Planning Committee, it will need to return to the committee to amend the requirements. Councils have advised it may be faster to conclude your application in its current form (with the old conditions) and then immediately apply to vary the conditions via an s.73 application.
Future changes
This move to 110 lpd is a clear target, but it is not the end of the story.
It is acknowledged that discussions are ongoing regarding tighter national standards being introduced. There is a current national consultation on amending the Building Regulations to 100 lpd for residential use in water-stressed areas. The current 110 lpd standard may soon be tightened.
Furthermore, the National SuDS guidance recognises that Rainwater Harvesting (RWH) should be promoted. The guidance (1.11) states RWH “shall be considered” where a development is in an area “identified as seriously water stressed.
Non-potable use
1.11 Rainwater harvesting shall be considered in all circumstances where any of the following apply.
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2. There is a need for landscape irrigation.1. There is a demand for non-potable water and available contributing catchment area that will deliver safe and efficient water savings.
- The development is in an area identified as seriously water stressed
Note: examples for 1.11.1 include industrial, commercial, horticultural, educational, public sector, residential and multiple-occupancy buildings.
Further insights into the National SuDS guidance can be found here, and more about how Aegaea can help with Surface Water Drainage Strategy through use of SuDS here.
How Aegaea can help
Aegaea has supported water neutrality projects, helping teams assess water demand and consider measures for their proposals. This announcement brings a close to our WNS work but there is still a requirement for Water Efficiency Statements.
If Aegaea can help with any of your water efficiency or Surface Water Drainage requirements, please do let us know. Our team can help establish the evidence and scope of work needed for your proposal.
