Previously developed land
Building Safety Levy brownfield rate: the 75% test and the half rate
Updated
A scheme on brownfield land pays half the standard rate, if it meets the 75% test.
Talk to a specialist The council, the floorspace and whether the site is brownfield. The rates come from the Regulations.
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How this calculator works
- The rates. Schedule 3 of the Building Safety Levy (England) Regulations 2025 sets a rate per square metre for each of 298 local authority areas, a previously developed land rate and a standard rate, from £6.35 and £12.70 in County Durham to £50.17 and £100.35 in Kensington and Chelsea. The calculator carries every row. (The Building Safety Levy (England) Regulations 2025, Schedule 3: rates by local authority)
- The calculation. The levy is the area rate times the chargeable floorspace. The government's own worked example: 20 houses of 100m² on previously developed land in Dover at £15.19 per m², £30,380. (GOV.UK: Building Safety Levy technical consultation, government response)
- Who pays and when. The levy applies from 1 October 2026 to building control applications and initial notices for new residential development in England, unless exempt. Developments of fewer than 10 new dwellings, or fewer than 30 PBSA bedspaces, are exempt. (Guildford Borough Council: Building Safety Levy information for developers)
- The brownfield rate. The discounted rate is 50% of the standard rate and applies where at least 75% of the land within the planning red-line boundary is previously developed land. (Telford & Wrekin Council: Building Safety Levy)
- Not tested. The calculator does not test the other exemptions (affordable housing, certain care and specialist housing, and others the Regulations list), how floorspace is measured on a mixed-use scheme, or any refund. The collecting authority's levy notice is the figure you pay.
The test
To qualify for the discounted rate, at least 75% of the land within the planning permission red-line boundary must be previously developed land.
Source: Telford & Wrekin Council: Building Safety Levy
The discount
The discounted rate is 50% of the standard levy rate, set for works on previously developed land.
Source: UK Parliament: written statement on the Building Safety Levy
Worked example
The government's own: 20 houses of 100m² on previously developed land in Dover at £15.19 per m², a levy of £30,380.
Source: GOV.UK: Building Safety Levy technical consultation, government response