From 1 October 2026, the Building Safety Levy (BSL) will apply to most new residential developments in England. For developers, funders and their advisers, this is not simply a new line in the cost plan, it changes how projects need to be structured, monitored and reported on from day one.
What is the basis of the levy?
The Levy was introduced under the Building Safety Act 2022 to fund the remediation of defective cladding and other historic building safety defects, on the principle that residents and taxpayers should not carry that cost. It is expected to raise more than £3bn over the next decade, collected directly from the development industry.
It will apply to:
- Residential developments of 10 or more dwellings
- Purpose-built student accommodation of 30 or more bedspaces
- Mixed-use schemes that meet these thresholds
Affordable housing, not-for-profit registered provider homes, NHS and care facilities, supported housing, and a handful of other specialist uses are excluded. Crucially, the Regulations include anti-avoidance provisions, splitting a single scheme into smaller applications to dodge the threshold will not work.
The charge itself is calculated on a per-square-metre gross internal area basis, with rates set individually by each local authority to reflect local house prices. Higher-value boroughs carry higher rates; a 50% discount applies where at least 75% of the site qualifies as brownfield land.
Why this matters beyond the finance team
For anyone involved in appraising, funding or monitoring a development, the Levy introduces three practical shifts.
- It becomes a completion risk, not just a cost line
No completion certificate, and therefore no legal occupation will be issued until the Levy has been paid in full. There is no provision for staged payment, even on phased schemes. That turns the Levy into a genuine programme risk: a funder or employer’s agent needs line of sight on levy liability well before practical completion, not as an afterthought once the building is watertight. Payment will be due prior to completion, or prior to occupation, whichever comes first.
- It adds a new information dependency at the front end
Levy calculations depend on dwelling numbers, floorspace and brownfield status, all of which must be submitted with the building control application and again at commencement. Get this wrong, or omit it, and the application itself can be rejected, creating delay before a spade is even in the ground. For appraisals and cost plans, this means levy exposure needs to be modelled early and revisited if scheme design changes, since any variation in chargeable floorspace during construction must be reported and can alter the liability.
- It sits on top of an already stacked cost base
The Levy will apply alongside existing obligations such as the Residential Property Developer Tax, CIL and section 106 contributions. Industry bodies have already raised concerns about cumulative burden on scheme viability, particularly for SME developers and sites in lower-value areas where the brownfield discount offers little relief. Viability testing at appraisal stage now needs to treat the Levy as a fixed, non-negotiable cost, not a variable that can be traded off against other obligations.
The pre-October window
Building control applications, initial notices and applications for higher-risk buildings submitted before 1 October 2026 are exempt, along with variation applications tied to a pre-deadline original submission.
For schemes already moving through design and pre-construction, this creates a genuine, if narrow, window to lock in exemption by bringing forward the building control submission. That is not a decision to make lightly: accelerating an application has knock-on effects for design freeze, procurement and (for higher-risk buildings) Gateway requirements. But for schemes sitting close to submission-ready, it is worth a deliberate, advised assessment now rather than a scramble in September.
What this means for how we work with clients
As a firm operating across Development Monitoring, Building Consultancy, Cost Consultancy, and Project Management we see the Levy landing at several points in a project’s lifecycle simultaneously:
- At appraisal and cost planning stage, levy liability needs to be calculated against the correct local authority rate and brownfield status from the outset, not bolted on retrospectively.
- In development monitoring reports to funders, levy status, whether a liability notice has been issued, whether it has been paid, and how it interacts with drawdown and completion milestones is fast becoming a standard reporting line, alongside build cost, programme and contingency.
In project and programme management, levy payment needs its own line in the completion critical path, particularly on phased developments where the “no staged payment” rule can catch cashflow planning off guard.
In early-stage advice, clients with schemes approaching building control readiness deserve a clear-eyed assessment of whether accelerating submission ahead of October is genuinely achievable and worthwhile, or whether the disruption outweighs the saving.
The Levy is not yet fully bedded in, rates are subject to review every three years, and the regulations are still relatively new. What is certain is that from October, it becomes part of the standard due diligence any funder, developer or monitoring surveyor needs to run on every qualifying residential scheme in England.
If you’d like to talk through how the Levy affects a specific scheme’s appraisal, programme or funding monitoring requirements, our team would be glad to help:
Mark Merritt
Director of Development Monitoring
James Gregory