Natural England and SSSIs: What It Means for a Planning Application

A planning application near a Site of Special Scientific Interest (SSSI) can be referred to Natural England, the government body that protects England's SSSIs. Natural England advises the council on whether the scheme could harm the site. It formally objects to fewer than 1% of the applications it sees, but the scheme cannot go ahead until the council is satisfied on every point Natural England raises. For most housing schemes the link to an SSSI is water: where the drainage goes, and what is in it.

A request for "further information" is not an objection, but it can stop a decision for weeks or months.

What is an SSSI, and who protects it?

An SSSI is land protected by law for its wildlife, habitats or geology. There are just over 4,100 in England, covering more than 1.1 million hectares or about 8% of the country, and Natural England notifies each one, monitors its condition and advises on anything that could damage it (Natural England).

Many SSSIs are also habitats sites of international importance: Special Areas of Conservation, Special Protection Areas or Ramsar wetlands, which bring the stricter tests of the Habitats Regulations on top of SSSI protection and give Natural England a second, separate role in the decision.

Condition matters.

As of March 2025, only 62% of SSSIs were in favourable or recovering condition.

The figure comes from Defra's biodiversity indicators, published in February 2026. A site already under pressure, for example from poor water quality, leaves little room for a new development to add to the problem.

When does a planning application go to Natural England?

Natural England is a statutory consultee: the council has to ask its advice on development in or likely to affect an SSSI, and on any appropriate assessment under the Habitats Regulations. A scheme does not need to be next to the site. The council decides whether to consult by checking the location against Natural England's SSSI Impact Risk Zones.

1. The council checks the Impact Risk Zone. Each zone lists the types of development that could harm the nearest SSSI, from large housing schemes to anything with its own water supply.
2. The zone says whether to consult. If the proposal matches a listed category, the council consults Natural England. If it does not, there is normally no need.
3. Natural England has 21 days to respond. That is the statutory deadline for a substantive response (GOV.UK).
4. The council weighs the advice. It decides the application, but it must take Natural England's advice into account and justify any decision that goes against it.

The zones are mapped on the government's MAGIC website, explained in the guide to the MAGIC map, and the wider consultee system is set out in how statutory consultees work in planning.

One category reaches almost every scheme with its own drainage. The zones treat "any discharge of water or liquid waste that is discharged to ground or to surface water" as a possible risk (Natural England IRZ guidance). A soakaway, a ditch outfall or a small sewage treatment plant can be enough. That makes water quality part of any surface water drainage strategy for planning near an SSSI from the first layout, alongside the flow rates the lead local flood authority checks.

Can you build on or near SSSI land?

Yes, but the bar is high. The August 2026 National Planning Policy Framework (NPPF) says development affecting an SSSI should only be supported if one of three things applies, and the test covers land outside the SSSI as well as inside it.

Policy N6(3) applies this to development "on land inside or outside a designated area" (NPPF), so a scheme a kilometre away is judged in the same way as one on the boundary if its drainage reaches the site. For habitats sites the test is stricter: the application should be refused unless an appropriate assessment finds no adverse effect on the site's integrity, or an Environmental Delivery Plan covers the impact.

The law adds a further step. If a council plans to approve a scheme against Natural England's advice, it must tell Natural England, explain how it took the advice into account, and wait at least 21 days before the work can start (GOV.UK SSSI duties). A decision against Natural England has to be justified in writing and can be challenged in the courts. Its advice therefore carries great weight.

What happens when Natural England delays an application?

A Natural England SSSI consultation response takes one of four forms, and only one of them lets the application move straight on.

Natural England's chair has said it objects to fewer than 1% of the planning applications it is consulted on (Planning Resource). That figure counts formal objections only. It leaves out "further information required" responses, which is where the delay sits. Each round means new evidence, a fresh consultation and another response period. Weeks turn into months.

Staffing makes it worse. In 2013/14 only 0.3% of applications missed a deadline because Natural England lacked the resources to meet it (Prospect).

By 2022-23, 1,952 planning deadlines, 11% of applications, were missed because Natural England did not have the staff to meet them.

Performance has improved since, with 89% of consultations answered on time in 2024-25 (Natural England annual report), but one in ten is still late.

Unda's own experience on schemes near protected wetlands shows the practical cost. On one housing scheme draining to a protected wetland, Natural England accepted the surface water design once every source of runoff passed through two stages of treatment, but then advised the council not to grant permission on the foul drainage, saying any discharge "should conform to the stringent water quality targets for the sites", without stating what those targets were. On other jobs, Natural England has objected because a scheme did not meet its technical criteria, then said it did not have capacity to explain what those criteria were. For the developer the result is the same each time. A consented scheme cannot start, the finance and build programme slips, and design fees go on guessing at a standard nobody has written down.

The consequences for a scheme can be severe:

• Months of delay. Each "further information" round adds a new consultation and response period, and a pre-commencement condition cannot be discharged until Natural England is satisfied.
• Redesign late in the process. Drainage, layout or treatment can change after permission, when changes cost most.
• Unviable schemes. Where mitigation depends on credits or a levy, the cost can remove the margin on a small site.
• Refusal. An unresolved objection from Natural England gives the council strong grounds to refuse.

Drainage: the pathway most schemes miss

Water is how most small and medium schemes affect an SSSI. Natural England wants evidence that what leaves the site will not change the water that reaches the protected site, and the first submission is the place for it.

Evidence supplied after a "further information" response costs a full consultation round.

• Surface water treatment. Runoff from roofs, roads and parking carries silt, oil and metals. Where a discharge reaches a sensitive site, Natural England has asked for at least two stages of treatment in a SuDS management train, assessed with the CIRIA C753 simple index approach. The CIRIA SuDS Manual sets out the method.
• Foul drainage without a sewer. A package treatment plant discharging to a ditch or the ground is one of the commonest triggers. The foul drainage strategy needs the plant's performance data, a maintenance plan and evidence it meets the receiving water's standards, not a condition promising details later.

Two other regimes sit alongside Natural England's advice. In 27 catchments, new homes must show they will not add nitrogen or phosphorus to protected sites, and SuDS can reduce that nutrient budget, as the guide to nutrient neutrality explains. A sewage discharge may also need an environmental permit from the Environment Agency, and an outfall to a ditch may need consent from an internal drainage board or the lead local flood authority, each with its own standards.

A worked example is Unda's drainage design for 24 homes on clay draining to an SSSI, where storage, flow controls and two-stage treatment were built around a single outfall. For schemes with conditions already attached, the discharge of drainage planning conditions service covers the evidence the council and its consultees need.

Consent and assent for work on SSSI land

Planning permission is not the only approval where work touches an SSSI directly. Every SSSI has a list of operations that need Natural England's consent, such as changing drainage or grazing, and although Natural England aims to decide within 28 working days it can take up to four months (GOV.UK SSSI consent). Planning permission does not replace it.

Public bodies face a separate duty. The Environment Agency, lead local flood authorities, internal drainage boards and water companies must get Natural England's assent before their own works that could damage an SSSI, and must consult it before permitting other people's works. That covers ordinary watercourse consent and flood risk activity permits on watercourses running into an SSSI. Damaging an SSSI without consent can bring an unlimited fine.

No decision on SSSI consent within four months counts as a refusal.

What changed in 2025-26?

The Planning and Infrastructure Act 2025 and the August 2026 NPPF changed how Natural England works with the planning system. The triggers for consulting it did not change.

• A narrower duty to advise. The government says the Act removed Natural England's duty to advise on every council request, so it can focus on "high risk and high opportunity casework" (government response, August 2026). Natural England is to publish an Operational Statement setting out its priorities. Lower-risk schemes near an SSSI should expect more reliance on standing advice and fewer tailored responses.
• Environmental Delivery Plans. Natural England can now prepare plans that deal with an impact, such as nutrient pollution, across a whole area, paid for by a nature restoration levy. The first, for nutrients in Norfolk, opened for consultation in September 2026 (Defra). Paying the levy is one of the three routes through NPPF Policy N6.
• More funding. The government has committed £100 million to modernise environmental planning services across Natural England, the Environment Agency and the Forestry Commission.
• No new SSSIs since 2023. A report by the campaign group Wild Justice found that no new SSSI has been notified in England since 2023 (Buglife). Existing sites and their Impact Risk Zones are unchanged.

For water neutrality, withdrawn in Sussex in October 2025, see the water neutrality guide.

Planning near an SSSI

When Natural England will be consulted is predictable: the Impact Risk Zones say so, and the NPPF says what it will test. What it will accept is less predictable. Most delay comes from evidence that arrives late or incomplete, and some from standards that are never written down. Check the zones before the layout is fixed, treat any discharge to ground or water as the likely trigger, and submit drainage evidence that answers Natural England's questions before it asks them. Unda prepares foul drainage strategies and surface water drainage strategies for sites near SSSIs and habitats sites across England and Wales. Call 01293 214444 or email enquiries@unda.co.uk.

Frequently asked questions