Chargeable development under the levy
Chargeable development is the development the permission allows, charged on net additional gross internal area. The measurement rules, the six month in-use test and the notices that decide whether an exemption survives.
Chargeable development cil is a defined term, not a description. Under the Community Infrastructure Levy Regulations 2010 the chargeable development is the development for which planning permission is granted, and the charge is calculated from the net additional gross internal floorspace it creates, multiplied by the rate in the charging authority's published schedule and adjusted for indexation. Two houses of identical size on identical plots can attract very different charges, because the deduction for what was already there is where most of the variation sits.
Understanding the arithmetic is the only way to check a bill.
What makes development chargeable
A charge arises where planning permission is granted for development in an area with an adopted charging schedule, and the development creates net additional floorspace above the threshold in the regulations. Not every permission attracts a charge. Development creating less than 100 square metres of new build floorspace is exempt unless it creates a dwelling, in which case the exemption does not apply.
Three things follow from the definition being tied to the permission.
The charge is calculated on what the permission allows, not on what you eventually build. Building less than the approved scheme does not reduce the charge unless the permission itself is varied. A section 73 permission to vary a condition triggers a recalculation, which can help or hurt depending on what changed. And where a permission is implemented in phases and each phase is a separate chargeable development, the liability and the notices apply phase by phase.
Measuring gross internal area
The measurement standard is gross internal area, and it is measured to the internal face of the external walls. That means internal walls, partitions, stairwells, lift shafts, plant rooms and integral garages are all inside the measurement. Open balconies, external steps and open covered areas are generally outside it.
Small measurement decisions move the number more than people expect on a single dwelling. A loft area with a floor and access counts if it is within the enclosing structure. A detached garage is a separate building and is measured separately. A basement counts in full.
Charging authorities publish their own measurement guidance, and the professional measurement practice published by RICS is the usual reference. Where your figure and the authority's differ, ask which drawings and which standard they measured from before arguing about the total, because the disagreement is usually about a stairwell or a garage rather than about the method.
The in-use building deduction
This is the part to read twice. Where the scheme involves demolishing or converting an existing building, the floorspace of that building can be deducted from the chargeable area, but only if it qualifies as an in-use building.
The test is that the building was in lawful use for a continuous period of at least six months within the three years ending on the day planning permission first permits the chargeable development. Meet the test and the existing floorspace comes off. Fail it and the whole of the new floorspace is chargeable even though a building stood there.
| Situation | Deduction available |
|---|---|
| Occupied house demolished and replaced | Yes, on the evidenced floorspace |
| Building empty for four years before permission | No |
| Barn in agricultural use converted to a dwelling | Yes, if the six month test is met on the evidence |
| Part of a building retained and reused in the scheme | Yes, retained floorspace is deducted |
| Building demolished before permission was granted | Generally no, since there is nothing in lawful use at the relevant date |
Evidence is on the applicant. Council tax or business rates records, utility bills, tenancy agreements, photographs with dates, and in agricultural cases subsidy records or veterinary and feed invoices all help. Assemble it before submitting the application rather than after the liability notice arrives, because by then the relevant date has passed and you cannot improve the position.
Illustrative example: a self-builder buys a plot with a derelict bungalow of 78 square metres, empty for five years, and replaces it with a 190 square metre house. No in-use deduction is available, so the chargeable area is the full 190 square metres rather than 112. The difference is a five figure sum in many charging areas, and it was decided before the plot was bought.
Exemptions and relief
Several exemptions and reliefs exist, and the procedure defeats more claims than the substance does.
- Self-build exemption for a dwelling built by or on behalf of the owner and occupied as their sole or main residence for at least three years after completion.
- Residential annexe and residential extension exemptions for works within the curtilage of an existing dwelling.
- Social housing relief, and charitable relief where the development is for a charity's charitable purposes.
- Exceptional circumstances relief, but only where the charging authority has resolved to make it available.
Every one of them has to be claimed on the correct form and granted in writing before development starts, and every one of them is lost if the commencement notice is not submitted first. The self-build exemption also carries a clawback: sell or let the house within three years of completion and the exemption is withdrawn and the charge becomes payable.
If you are building your own home, treat the paperwork as part of the build programme with its own dates, alongside the reports your application needs. You can browse the report types a self-build application typically requires while you are at it.
The notices and what each one does
The sequence is procedural and unforgiving:
- Liability notice, issued by the collecting authority after permission is granted, setting out the chargeable amount and who it thinks is liable.
- Assumption of liability, submitted by whoever will pay. If nobody assumes liability, it falls on the landowner by default, along with any surcharge.
- Any exemption or relief claim, submitted and determined before work starts.
- Commencement notice, submitted before development starts, stating the intended start date.
- Demand notice, issued after the start, setting out the amount and the payment dates.
Miss the commencement notice and the consequences are immediate: instalment entitlement is lost, a surcharge is applied, any exemption falls away and the full amount becomes payable at once. The authority can also determine a deemed start date if it believes work began earlier than stated.
Indexation and payment triggers
The rate in a charging schedule is stated in pounds per square metre at a base date, then indexed. The chargeable amount uses the published annual index for the year in which permission was granted against the index for the year the charging schedule took effect, so a schedule adopted years ago produces a higher figure today than its face value.
Payment is due within a fixed period after the development starts unless the charging authority has adopted an instalment policy. There is no national instalment entitlement, so read the local policy before modelling cash flow. Instalment policies commonly step payments by scheme size, and losing the entitlement through a late commencement notice converts a staged payment into a single one.
Checking a charge before paying it
Liability notices contain errors, and the routes to challenge them are time limited.
Start by asking the collecting authority for its calculation: the gross internal area it used, the drawings it measured, the deduction it applied or refused, the rate and the index figures. Four things go wrong most often. The measurement includes something that should be outside it. The in-use deduction has been refused on evidence the authority never saw. The wrong rate has been applied, often a residential rate to a mixed scheme. Or the index for the wrong year has been used.
Where there is an arithmetic or measurement dispute, the regulations provide for a review of the chargeable amount by the charging authority, to be requested within a short period after the liability notice, followed by an appeal to the Valuation Office Agency. Separate appeal routes exist for apportionment, for the annexe and self-build exemptions, for surcharges and for a deemed start date. The review, appeal and surcharge routes run on their own clocks, and a challenge to the calculation itself has to be made before those clocks run out.
Pay attention to the dates on the notice the day it arrives. A calculation error you can prove is worth nothing once the review period has closed.
This is general guidance rather than legal advice. Check the position with your local planning authority or a qualified professional before relying on it.
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Frequently asked questions
What is a chargeable development for levy purposes?
It is the development for which planning permission is granted, in an area with an adopted charging schedule, where net additional gross internal floorspace is created. Development of less than 100 square metres of new build is exempt unless it creates a dwelling. The charge is based on what the permission allows rather than on what is eventually built.
What counts as gross internal area?
Floorspace measured to the internal face of the external walls, which includes internal walls, partitions, stairwells, lift shafts, plant rooms and integral garages. Open balconies, external steps and open covered areas are generally excluded. Basements count in full. Charging authorities publish their own measurement guidance alongside the professional measurement practice published by RICS.
When can I deduct an existing building from the chargeable area?
Where the building was in lawful use for a continuous period of at least six months within the three years ending on the day planning permission first permits the development. Evidence such as council tax records, utility bills, tenancy agreements and dated photographs is on the applicant. A long-empty building gives no deduction at all.
How do I keep the self-build exemption?
Claim it on the correct form and have it granted in writing, submit the commencement notice before any work starts, and occupy the completed dwelling as your sole or main residence for at least three years. Selling or letting within that period withdraws the exemption and the charge becomes payable.
Can I challenge a levy liability notice?
Yes, but the time limits are short. Ask the collecting authority for its calculation, then use the regulations' review of the chargeable amount by the charging authority followed by an appeal to the Valuation Office Agency. Separate routes cover apportionment, the annexe and self-build exemptions, surcharges and a deemed start date.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.