Building Safety Levy October 2026: What Residential Developers Must Budget For
The Building Safety Levy starts in October 2026. Any building control application for a new residential development submitted on or after the commencement date is subject to a per-m² charge on residential GIA. Here is how it is calculated, who is exempt, and how it affects development appraisals.
Last reviewed by the Homedata editorial team — 15 April 2026
The Building Safety Levy starts in October 2026. Any building control application for a new residential development in England submitted on or after the commencement date will be subject to the charge. For developers with schemes currently in appraisal or planning, this is a cost line that needs to be in the model now.
The levy is the Government's mechanism for funding cladding remediation on buildings where the original developer cannot be identified or held responsible. It was introduced under the Building Safety Act 2022, with the detailed regulations and rates confirmed in 2026.
How the levy works
The levy is charged per square metre of gross internal area (GIA) of new residential floorspace. It is payable when a building control application is submitted — not at planning stage, not at completion. The developer (or applicant) pays.
The rate is not uniform. It varies by:
- Local authority area — the country is divided into bands broadly reflecting land and development values. Central London local authorities carry the highest rates; rural and lower-value areas the lowest.
- Whether the units are market sale or market rent — the rates differ between build-for-sale and build-to-rent (the Government has confirmed different rate tables for each).
The Government has published the rate tables by local authority on GOV.UK. For planning purposes, the range runs from approximately £20/m² in lower-rate areas to over £80/m² in Central London [GOV.UK]. Always check the current published rates for the specific local authority — they may be updated before October 2026.
What is exempt?
The following are exempt from the Building Safety Levy:
- Affordable housing — units to be sold or let at affordable rent or shared ownership, provided they meet the relevant definition. The exemption applies to those specific units, not to the whole scheme if there are also market units.
- Registered social landlords — whole-scheme exemption where the registered provider is the developer.
- Self-build — a single dwelling for personal occupation where the applicant is building their own home.
- Small developments — developments of 10 or fewer units may qualify for a reduced or nil rate in some categories. Check the current regulations for the exact threshold.
Non-residential elements of a mixed-use development are not subject to the levy — only the residential GIA is counted. For a scheme with ground-floor commercial and residential above, the levy applies to the residential floorspace only.
How to calculate the levy for a scheme
The calculation is straightforward once you have the GIA:
- Identify the local authority for the development.
- Look up the rate for that local authority in the Government's rate tables.
- Calculate the total residential GIA in m².
- Deduct any exempt affordable housing GIA.
- Multiply the chargeable GIA by the applicable rate.
Example for a 50-unit scheme in a mid-rate local authority:
| Item | Figure |
|---|---|
| Total residential GIA | 3,500 m² |
| Affordable housing GIA (20% of units) | 700 m² (exempt) |
| Chargeable GIA | 2,800 m² |
| Rate (mid-band, market sale) | £50/m² |
| Levy payable | £140,000 |
For a scheme in Central London at £85/m², the same 2,800 m² of chargeable GIA would attract a levy of £238,000.
Where the levy sits in a development appraisal
In a residual appraisal, the levy is a development cost that sits alongside:
- Community Infrastructure Levy (CIL)
- Section 106 contributions
- Stamp Duty Land Tax on land acquisition (see GOV.UK SDLT rates)
- Build cost (BCIS)
- Professional fees
- Finance costs
All four public levies — CIL, S106, SDLT on the land, and now the Building Safety Levy — reduce the residual land value that the developer can offer. For sites in the planning pipeline where a land price has already been agreed, a levy that was not originally modelled will compress the developer's margin unless the land price is renegotiated.
For appraisal purposes, treat the levy as a day-one cost (payable on building control application, typically before construction begins) rather than an end-of-development cost. Discounting it to net present value has minimal effect given the payment timing, but it is a real cash outflow in the early project phase.
Impact on viability assessments
Where a scheme already has marginal viability — particularly in lower-value residential markets where profit on GDV is already thin — the Building Safety Levy adds pressure. Viability assessments submitted to local planning authorities for affordable housing negotiations should now include the levy as a modelled cost.
Local planning authorities are aware of the levy's introduction. The Planning Inspectorate has confirmed that the levy should be included in viability evidence submitted after October 2026. Appeals based on viability assessments that do not account for the levy are unlikely to succeed.
What developers should do before October 2026
- Audit schemes in the pipeline. For any scheme with a building control application likely to be submitted after October 2026, calculate the levy exposure and update the development appraisal.
- Check local authority rate. Rates vary significantly. A scheme on the boundary of two local authority areas may attract materially different levy charges — verify the correct authority.
- Identify affordable housing GIA accurately. The exemption for affordable units is valuable. Ensure the scheme's affordable housing quantum and distribution is accurately reflected in the GIA calculation.
- Update land bids. For sites where heads of terms have not yet been agreed, the levy should be in the appraisal. For sites where a land price is already agreed, consider whether the levy changes the scheme's viability.
- Brief your building control body. Approved inspectors and local authority building control teams are processing applications and will be collecting the levy from October. Ensure your project team knows the payment process.
What this could look like as a development appraisal tool
Levy calculator concept
A development feasibility tool could incorporate Building Safety Levy rates by local authority alongside SDLT, CIL estimates, and S106 ranges. The Homedata property data API provides the comparables (sold prices, floor areas) that underpin GDV calculations — combining those with a levy lookup by postcode gives developers a single appraisal environment. See our guide: How to Calculate Property Development Feasibility in the UK.
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