Natural England has raised significant concerns regarding the potential adverse impact of current groundwater abstraction, managed by Southern Water, on habitat integrity at environmentally designated sites, including Amberley Wild Brooks Site of Special Scientific Interest (SSSI), Pulborough Brooks SSSI and Arun Valley Special Protection Area (SPA), Arun Valley Special Area of Conservation (SAC) and Arun Valley Ramsar site. The groundwater abstraction supplies potable water to the North Sussex Water Supply Zone (NSWSZ), which covers district councils of Horsham and part of Chichester, part of Crawley Borough Council (except Gatwick Airport and Maidenbower) and part of the South Downs National Park.

Investigations and discussions between Southern Water, the Environment Agency and Natural England on the long-term sustainability of the existing abstraction are ongoing, including a sustainability investigation to assess what level of ground and surface water abstractions are sustainable. In the meantime, Natural England has advised the Local Planning Authorities (LPAs) that development in the NSWSZ region must not add to this potential adverse effect. This can be achieved by making developments within the zone “water neutral”. In other words: “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.”