Water Neutrality and Horsham District

Water Neutrality in Horsham?

Water neutrality means any new development must not increase the total demand on Southern Water’s Sussex North Water Resource Zone, which sources from the ecologically sensitive Arun Valley (Horsham District Council). Introduced following Natural England’s 2021 position, this requirement ensures that housing growth doesn’t exacerbate impacts on protected habitats.

Why the Arun Valley is At Risk

The Arun Valley contains habitats protected under the Habitats Regulations, hosting rare species that are threatened by increased abstraction. Natural England concluded that ongoing water use in the region is already harming these sites—prompting the call for water neutrality (Horsham District Council, Horsham District Council).

Immediate Planning Impacts

Since 2021, Horsham District Council has halted granting permissions for housing or commercial schemes that increase mains water demand—unless offset-neutral measures are proven (Horsham District Council). This has effectively slowed development, with applications paused while developers demonstrate their water neutrality credentials.

Local Plan Delays & Strategic Constraints

Water neutrality considerations forced a pause in Horsham’s Local Plan process from 2021 onwards (Our District). The authority has since modelled future water demand (Part A/B/C studies), setting efficiency standards and devising offsetting mechanisms before finalising housing allocations (Horsham District Council).

Offsetting Pathways: SNWCS, Boreholes, Private Schemes

To meet neutrality, Horsham and neighbouring councils launched the Sussex North Offsetting Water Scheme (SNOWS)—an offsetting system tied to Southern Water’s WRMP24 savings (Horsham District Council) but it is not currently available to everyone.

Long-Term Planning & Collaboration Impacts

While this approach safeguards the Arun Valley, it has strained housing supply—Horsham’s Local Plan currently proposes 480 homes/year rising to 901/year, resulting in an unmet need of ~2,300 homes over the plan period (CPRE Sussex). Moreover, an inspector recently flagged a legal failure of the Duty to Co-operate, citing inadequacies in addressing water neutrality through strategic collaboration (urbanissta.co.uk).

Conclusion

Horsham District’s water neutrality policy—anchored in environmental legislation—has reshaped development strategies, delaying planning processes and capping housing delivery until robust offsetting is in place. Through the SNWCS scheme, borehole strategies, and efficiency mandates, local authorities are striving to balance ecological protection with essential growth. However, long-term expansion will most likely rely on strengthening cross-boundary coordination and operational sustainable neutrality frameworks.

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