BNG Reforms July 2026: The 0.2 Hectare Exemption and What It Means for Residential Planning

Last updated: June 25, 2026

Quick Answer: The UK Government has confirmed a new area-based exemption under the BNG reforms July 2026 package, removing Biodiversity Net Gain requirements for residential planning applications on sites of 0.2 hectares or below (unless priority habitats are present). Expected to come into force before 31 July 2026, this single change is projected to exempt approximately 50% of all residential planning permissions from BNG obligations — the most significant shift since mandatory BNG was introduced under the Environment Act 2021.

Key Takeaways

• Sites of 0.2 hectares or below are exempt from BNG requirements under the new rules, subject to no priority habitats being present on site.
• The Government expects this area-based exemption to remove roughly 50% of residential planning permissions from BNG obligations.
• Reforms are expected to come into force before 31 July 2026, subject to parliamentary scheduling.
• BNG will extend to Nationally Significant Infrastructure Projects (NSIPs) from 2 November 2026.
• The statutory Biodiversity Metric will be updated as part of the same reform package.
• A separate brownfield housing exemption (up to 2.5 hectares) is under consultation; it is not yet in force following the consultation closure on 10 June 2026.
• SME developers and small-site housebuilders stand to benefit most; NSIP promoters face new compliance obligations.
• The off-site BNG unit market may soften for small residential sites, but demand from larger schemes and NSIPs is expected to continue.
• Landowners operating habitat banks should review their pipeline in light of shifting demand patterns.
• Priority habitat checks remain essential — exemption is not automatic without a site assessment.

What Is the 0.2 Hectare Exemption in the BNG Reforms July 2026?

The 0.2 hectare exemption is a new area-based rule that removes the mandatory BNG requirement for residential planning applications on sites of 0.2 hectares or below. It forms the centrepiece of the Government's BNG reform package, which DEFRA and the Ministry of Housing, Communities and Local Government have confirmed is expected to come into force before 31 July 2026.

Under the Environment Act 2021, mandatory BNG applies to most planning permissions in England, requiring a measurable 10% net gain in biodiversity value. The new exemption carves out a significant portion of the residential market from that obligation, provided one critical condition is met: no priority habitats must be present on the site.

The Government's stated rationale is to reduce administrative complexity for Local Planning Authorities, remove barriers for SME housebuilders, and address practical difficulties that emerged in the early implementation period following the February 2024 mandatory BNG rollout.

Which Residential Projects Qualify for the 0.2 Hectare BNG Exemption?

A residential development qualifies for the exemption if it meets both of the following conditions:

• Site area is 0.2 hectares or below (measured as the total application site boundary).
• No priority habitats are present on the site, as defined under Section 41 of the Natural Environment and Rural Communities Act 2006.

If either condition is not met, BNG requirements apply in full. Developers cannot self-certify without a baseline ecological check. A preliminary ecological appraisal or BNG metric assessment is still advisable to confirm priority habitat status before relying on the exemption.

Common project types likely to qualify:

• Single dwelling plots and small infill sites
• Small residential conversions where the curtilage is under 0.2 ha
• Modest flatted schemes on tight urban plots
• Self-build and custom-build residential projects on small plots

For a broader overview of which project types have historically been exempt, see the Exempt Projects guidance.

How Does the 0.2 Hectare Rule Differ from Previous BNG Requirements for Small Sites?

Before these reforms, the only area-based exemption for residential development was the "small sites" threshold introduced at mandatory BNG launch, which applied to sites of fewer than 10 dwellings or below 0.5 hectares. That threshold was widely criticised for still catching many genuinely small urban plots and for creating disproportionate compliance burdens on SME developers.

The new 0.2 hectare exemption works differently:

The shift to a pure area-based test simplifies decision-making for applicants and LPAs alike. For context on how the metric assessment process works for non-exempt sites, the BNG for small development projects guide remains a useful reference.

Do I Still Need a Biodiversity Survey for Developments Under 0.2 Hectares?

Not necessarily for BNG compliance purposes — but a survey is still strongly advisable. The exemption removes the obligation to submit a Biodiversity Metric calculation and secure BNG units, but it does not override other ecological obligations.

Developers should still consider:

• Priority habitat verification: If a Phase 1 habitat survey or Preliminary Ecological Appraisal (PEA) identifies priority habitats, the exemption does not apply and full BNG is required.
• Protected species: Surveys for bats, great crested newts, and other protected species remain legally required regardless of site size.
• Local planning authority requirements: Some LPAs may still request ecological information as part of their validation checklist.
• Due diligence: Relying on the exemption without a baseline check carries planning risk if priority habitats are later identified.

In short, a targeted ecological appraisal is still best practice for any residential site, even those expected to fall within the exemption. See how to conduct a biodiversity impact assessment for a practical overview of what that involves.

What Else Changed in the BNG Rules for Residential Planning in July 2026?

The 0.2 hectare exemption is the headline measure, but the July 2026 reform package contains several other confirmed changes:

1. Updated Statutory Biodiversity Metric
An update to the statutory Biodiversity Metric is included in the package. Developers, ecologists, and planning consultants should confirm which metric version applies to applications submitted after the reforms come into force.

2. BNG Extended to NSIPs from 2 November 2026
Nationally Significant Infrastructure Projects — including major energy, transport, and water infrastructure — will be subject to mandatory BNG from 2 November 2026. This is a significant expansion of scope and will create substantial demand for off-site BNG units from large-scale promoters. Landowners with habitat banks should take note.

3. Brownfield Housing Exemption Under Consultation
A proposed exemption for brownfield housing sites up to 2.5 hectares closed for consultation on 10 June 2026. No decision has yet been announced. If confirmed, this would represent a further substantial reduction in BNG obligations for urban regeneration schemes. Developers should not assume this exemption is in force — it is not.

4. Further Proposed Exemptions
Later in 2026, the Government intends to consult on exemptions for:

• Developments whose primary objective is to conserve or enhance biodiversity
• Developments that enhance parks, playing fields, and public gardens

How Does the BNG Exemption Affect the Off-Site Unit Market and Habitat Banks?

For landowners and habitat bank operators, the picture is mixed. The 0.2 hectare residential exemption removes a segment of demand that was, in practice, generating relatively small unit purchases. The larger concern for habitat bank operators would be if the brownfield exemption up to 2.5 hectares is confirmed — that would remove a more commercially significant tranche of buyers.

However, the extension of BNG to NSIPs from November 2026 creates a new and potentially substantial source of demand. Infrastructure projects typically have large footprints and significant biodiversity impacts, meaning unit requirements per scheme may be considerably higher than for residential developments.

Landowners considering entering the habitat bank market should review both the current demand landscape and the incoming NSIP requirements. The BNG off-site: land banking vs. habitat banking guide sets out the key distinctions between these routes. Those already operating habitat banks can also explore options via Sell Biodiversity Units.

What Happens If My Residential Site Is Slightly Over 0.2 Hectares?

If the application site area exceeds 0.2 hectares, the exemption does not apply and full BNG requirements remain in force. There is no tapering or partial exemption for sites just above the threshold.

For sites between 0.2 and 0.5 hectares, developers should:

1. Commission a Biodiversity Metric assessment to calculate the baseline biodiversity value.
2. Design the scheme to maximise on-site BNG delivery where possible.
3. Identify off-site unit options if the on-site gain cannot reach 10%.
4. Submit the completed Biodiversity Gain Plan with the planning application.

The 8 biodiversity net gain points on planning your project article covers the planning process in detail for sites that remain within scope.

Edge case to watch: Where a developer controls a larger plot but submits a planning application for only part of it, the LPA may consider the whole landholding when assessing the site boundary. Artificially splitting applications to fall below 0.2 hectares is likely to be challenged.

Does the BNG Exemption Apply to Social Housing and Affordable Residential Projects?

Yes. The exemption is area-based, not tenure-based. Social housing, affordable housing, shared ownership, and private market residential developments are all treated equally under the 0.2 hectare threshold. There is no separate rule for registered providers or local authority housing schemes.

This is particularly relevant for housing associations and councils delivering small infill affordable housing sites, which have historically faced disproportionate BNG compliance costs relative to scheme value.

Frequently Asked Questions

Q: When exactly do the BNG reforms July 2026 come into force?
A: The Government expects the reforms, including the 0.2 hectare exemption, to come into force before 31 July 2026, subject to parliamentary scheduling. Developers and LPAs should monitor GOV.UK for the confirmed commencement date.

Q: Does the 0.2 hectare exemption apply automatically, or do I need to declare it?
A: Developers will need to declare the exemption as part of the planning application process. LPAs will need to confirm that the site qualifies — particularly that no priority habitats are present. A baseline ecological check is strongly recommended before relying on the exemption.

Q: Is the brownfield housing exemption (up to 2.5 ha) already in force?
A: No. The consultation on the brownfield housing exemption closed on 10 June 2026. No exemption is yet in force. Brownfield sites above 0.2 hectares remain subject to full BNG requirements until any new exemption is formally enacted.

Q: Will the updated Biodiversity Metric affect existing planning applications?
A: Applications already submitted before the metric update comes into force should generally be assessed under the metric version applicable at the time of submission. Applications submitted after the update will use the new version. Confirm the position with your LPA or ecologist.

Q: Are NSIPs currently subject to BNG?
A: Not yet. BNG will apply to Nationally Significant Infrastructure Projects from 2 November 2026. NSIP promoters should begin BNG planning now, as baseline surveys and metric assessments for large infrastructure projects can take considerable time.

Q: Can a site with priority habitats still use the 0.2 hectare exemption?
A: No. The presence of priority habitats (as listed under Section 41 of the NERC Act 2006) disqualifies a site from the exemption regardless of its size. Full BNG requirements apply, and a Biodiversity Metric assessment will be needed.

Q: Does the exemption cover extensions and conversions?
A: The exemption applies where the planning application site area is 0.2 hectares or below. Small residential extensions and conversions on tight plots are likely to qualify on area grounds, but the same priority habitat caveat applies. Check with an ecologist if there is any doubt about habitat status.

Conclusion: What Should You Do Now?

The BNG reforms July 2026 represent a genuine and material change to the residential planning landscape. For SME developers, the 0.2 hectare exemption removes a compliance burden that has slowed small-site delivery since mandatory BNG launched in 2024. For NSIP promoters, the November 2026 extension means BNG planning should already be underway. And for landowners with habitat banks, the shifting demand picture warrants a strategic review.

Practical next steps by audience:

• SME developers and self-builders: Confirm your site area and commission a priority habitat check before assuming exemption. A targeted ecological appraisal is still best practice.
• Planning consultants and architects: Update your pre-application checklists to reflect the new threshold. Advise clients on the priority habitat caveat and the brownfield exemption's pending status.
• NSIP promoters: Begin baseline ecological surveys and Biodiversity Metric assessments now. November 2026 is closer than it appears for projects of this scale.
• Landowners and habitat bank operators: Reassess your unit pipeline against the new demand landscape, particularly the incoming NSIP market.

For sites that remain within BNG scope, a professionally conducted ecological survey and Biodiversity Metric assessment remain the foundation of a compliant and cost-effective approach. Biodiversity Surveyors provides both services, helping developers, landowners, and planning teams understand exactly where they stand under the new rules. Explore the guidance for developers or contact the team to discuss your specific project.

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