Water neutrality in Horsham: does it still affect your project?

If you are planning an extension, a garage conversion, or a new kitchen or bathroom in Horsham District, water neutrality is no longer something you have to deal with. Since 1 November 2025 Horsham District Council has required no water neutrality statement, no offsetting payment and no water neutrality condition on any application. If you are building a new home, there is still a water efficiency standard to meet, but it is a building specification, not the calculation and offsetting exercise it used to be.

What it was, and why Horsham

Much of Horsham District gets its mains water from Southern Water’s Sussex North Water Supply Zone. Part of that supply is groundwater pumped at Hardham, near Pulborough, close to the wetlands of the Arun Valley: Pulborough Brooks, Amberley Wild Brooks and Waltham Brooks. Together they are protected as the Arun Valley Special Area of Conservation, Special Protection Area and Ramsar site, which puts them under the Habitats Regulations.

In September 2021 Natural England advised that it could not rule out the abstraction harming those sites. Until that was resolved, new development in the supply zone had to show no net increase in water use (“water neutrality”), with calculations, a statement, and offsetting found elsewhere. A council-run offsetting scheme, first announced as SNOWS and later renamed the Sussex North Water Certification Scheme (SNWCS), was planned to make that easier.

What changed, and when

Southern Water’s study of the Hardham basin, completed in August 2025, found little or no connection between the abstraction and Waltham Brooks or Amberley Wild Brooks, but could not rule one out at Pulborough Brooks.

The answer agreed between Natural England, the Environment Agency and Southern Water was to cap the Hardham licence: from 16.44 to 13 megalitres a day on average, and from 30 to 27 at peak. That cap reflects what has actually been abstracted in recent years, so new homes cannot add to the pressure on the wetlands.

On that basis Natural England withdrew its position statement on 31 October 2025. Horsham District Council’s response, which still stands, is that from 1 November 2025:

• No water neutrality statement is required
• No payment into SNWCS is needed: the council is instead using some 3.24 million litres a day of water efficiency savings Southern Water made in 2024/25 to treat all development as water neutral
• No bespoke conditions or section 106 obligations are required to demonstrate water neutrality

SNWCS will not now launch.

The one loose end

The licence cap was expected to be in place by March 2026. When we last checked, in October 2026, the council’s water neutrality page still said the licence change had not yet taken place. Until it does, the council remains responsible under the Habitats Regulations, and its officers carry out an Appropriate Assessment as part of considering applications.

That is the council’s own check, not a document you produce. It is also a reason to look at the council’s page before you apply, rather than relying on anything written earlier, including this.

Who it still touches

New homes. Because the area remains under significant water stress, every application for new housing gets a condition requiring the Building Regulations Part G optional water efficiency standard, currently 110 litres per person per day, against 125 for the standard requirement. That comes from Policy 37 of the Horsham District Planning Framework, and it is the same condition the council applied to new dwellings before 2021. It shapes the choice of taps, showers, WCs and appliances.

Annexes. The 110-litre condition attaches to new housing. An annex that is used as part of the main house is not usually a new dwelling. One designed to be lived in as a separate home may well be. Which side of the line yours falls on is for the council to decide on the facts, so if your annex has its own front door, kitchen and bathroom, expect the question and ask it at pre-application stage. We took a self-contained garden home in Southwater through planning while water neutrality was in force, so we know how the question gets asked.

Extensions, garage conversions, kitchens and bathrooms. Nothing to submit on water. If the work needs permission, the application is an ordinary householder application. See whether your extension needs permission at all and what the application costs.

Properties in the South Downs National Park. Part of the Park, including part of its Horsham area, is inside the supply zone. The Park Authority has confirmed that development there no longer needs to show water neutrality either. If you are not sure which authority decides your application, check that first.

Looking for the map? The zone boundary is shown on Southern Water’s supply area map. For an extension or a refit, being inside it no longer changes what you submit.

If you have an old permission with a water neutrality condition

Permissions granted between 2021 and October 2025 often carry conditions or section 106 obligations tying the development to a water neutrality solution. The council has said it will consider applications under section 73 of the Town and Country Planning Act 1990 to remove those conditions, along with applications to vary or discharge the related section 106 obligations. Where the permission is for new dwellings, the council will replace the water neutrality condition with the 110-litre Part G condition.

A section 73 application carries a fee and takes time, so weigh it against the cost of building whatever the condition currently requires.

If someone quotes you for a water neutrality statement

On a householder extension, conversion or refit in Horsham District, there is nothing for a water neutrality statement to do. If a designer, consultant or builder includes one in a quotation now, ask what it is for. The likely answer is a template written before November 2025.

Where this comes from

The background and licence figures are from Natural England’s withdrawal statement of 31 October 2025; what applicants need to do now is from Horsham District Council’s water neutrality page.

What to do next

If the only thing that stopped you planning an extension was water neutrality, it is no longer a reason to wait. See how we approach home extensions, or tell us what you are planning and we will give you an itemised written quotation.