How a community infrastructure levy charging schedule works

A CIL charging schedule calculation is arithmetic, not judgement, and that is the useful thing about it. The levy is a rate in pounds per square metre, multiplied by the net additional floorspace you create, adjusted by an index. Unlike a section 106 contribution there is nothing to negotiate. What there is to get right is the floorspace measurement, the existing building offset and the sequence of forms, because an error in any of those costs real money and two of them cannot be fixed later.

Start with the schedule in force on the day permission was granted, not the one on the authority's website today.

What the levy charges, and what it leaves alone

The Community Infrastructure Levy Regulations 2010 charge the levy on net additional chargeable floorspace, measured as gross internal area. Development creating less than 100 m² of new floorspace is exempt as minor development, unless it comprises one or more dwellings, in which case the levy applies however small the house is.

That single exception is the one self-builders trip over. A 78 m² two-bedroom house is chargeable. A 95 m² extension to a commercial building is not.

Some things sit outside the charge entirely. Mezzanines inserted into an existing building, buildings into which people do not normally go, and structures which are not buildings. Change of use with no new floorspace generates no liability unless the existing building fails the in-use test described below.

The levy is also separate from section 106 obligations, and an authority cannot use both to fund the same item of infrastructure. Formula-based contributions are a different mechanism, and our note on open space and play space contribution formulas covers how those are calculated.

Reading the rates in a charging schedule

A charging schedule gives rates by development type and often by geographical zone. A typical structure looks like this.

Two practical warnings. Zone boundaries are drawn on a map that may be at a scale where your site straddles a line, so check the authority's own mapping rather than scaling it yourself. And the residual or all other development rate is frequently zero, which means a use that nobody expected is free, so read the definitions before assuming your scheme falls in the residential rate.

Where the authority has adopted a schedule and then revised it, the relevant schedule is the one in effect when permission was granted. For a long-running application that can mean the older, lower rate, and it is worth checking rather than accepting the figure on the liability notice.

The indexation that turns a rate into a figure

The rate in the schedule is not what you pay. Schedule 1 to the Regulations applies a formula that multiplies the rate by the chargeable area and then by the ratio of two index values: the index for the year permission was granted, over the index for the year the charging schedule took effect.

Since 2020 the index used is the levy index published annually by the Royal Institution of Chartered Surveyors, and charging authorities are required to publish an annual rate summary showing the indexed rates. Find that document. It converts the schedule's base rate into the figure that will actually appear on your liability notice, and it is the quickest way to sanity-check the authority's arithmetic.

For a schedule adopted some years ago, indexation can add a substantial proportion to the headline rate. Budget from the current rate summary, not from the schedule.

Measuring floorspace and claiming the existing building offset

Gross internal area is measured to the internal face of the external walls, following the RICS code of measuring practice, and it includes internal walls, stairwells, plant rooms and integral garages. It is not the net saleable area and it is not the figure on the estate agent's particulars.

The offset for existing floorspace is where most money is saved or lost. Existing floorspace can be deducted from the chargeable area, but only where the building qualifies as an in-use building, which means it has been in lawful use for a continuous period of at least six months within the three years ending on the day the permission first permits development.

So a barn empty for four years brings no offset. A shop that closed eight months ago and was trading for the previous two years does. The evidence required is the same kind you would use for a lawful development certificate.

1. Business rates records or council tax records for the relevant period.
2. Utility bills showing consumption rather than standing charges.
3. Accounts, leases or employment records.
4. Dated photographs and, where necessary, statutory declarations.

Where demolition is involved, the floorspace to be demolished counts towards the offset on the same in-use test. Submit the evidence with the additional information form at application stage, not after the liability notice arrives, because an authority that has already issued a notice has to be persuaded to review it.

The forms and the order they go in

Sequence matters more than content, and the order is the part self-builders get wrong.

1. The additional information form goes in with the planning application, setting out floorspace and any offset or relief claim.
2. The authority issues a liability notice after permission is granted, stating the chargeable amount.
3. Someone assumes liability, in writing, before work starts. If nobody does, liability falls on the landowner.
4. Any exemption or relief claim must be made and granted before work starts.
5. A Commencement Notice must be submitted before work starts, giving the intended start date.
6. The authority issues a demand notice setting out what is payable and when.

Step five is the one that costs people tens of thousands of pounds. Starting work without having submitted that notice exposes you to a surcharge and can put an exemption at risk. The Regulations have been amended on this point, so check the current provisions, but the safe practice is unchanged: notice in, acknowledgement received, then start.

Do not treat site clearance as neutral. Development starts, for levy purposes, on a material operation, which includes digging a trench for foundations and laying out a road, so the ground worker arriving before the notice goes in is a real risk.

Exemptions a self-builder can claim

Three exemptions matter at this scale, and all three have to be claimed, granted and followed up.

Self-build exemption applies where you are building a house to occupy as your sole or main residence. It is claimed in two parts: Part 1 before work starts, and Part 2 within six months of completion with supporting evidence, typically the title, a council tax bill, a completion certificate and the finance documents. Miss the Part 2 deadline and the full levy becomes payable.

Residential annex and residential extension exemptions apply to work at your own home, and the extension exemption matters because an extension of 100 m² or more would otherwise be chargeable.

All three carry a clawback period. Selling, letting or ceasing to occupy the dwelling as your main residence within three years of completion triggers repayment of the exempted amount, and the authority registers a local land charge to secure it. Plan around that before claiming.

When payment falls due, and how to challenge the figure

Payment follows the authority's published instalment policy, which typically splits the sum into two or three payments linked to the start date. Where the authority has no instalment policy, the whole amount is due within 60 days of the start date, which is a cashflow problem worth knowing about before you start.

Three routes exist to challenge a figure, and they are short.

• A review of the chargeable amount, requested from the charging authority within 28 days of the liability notice, on the ground that the calculation is wrong.
• An appeal to the Valuation Office Agency after the review, on the chargeable amount, and separate appeals against surcharges and against a determination on relief.
• A judicial review, which is a last resort and tests legality rather than arithmetic.

None of these is an appeal against the rate itself. The schedule was examined when it was adopted and the rate is not open to challenge on an individual application, which is why the measurement and the offset are where the work pays off.

Budget the levy alongside your professional fees and report costs, and see PlanScope pricing for what drafting the supporting documents costs: one free report, £50 per report, or £150 per month for unlimited reports. A Planning Statement is the right place to record an in-use claim in narrative form, with the evidence appended, and you can browse the full set of report types to see what else a small scheme needs.

This is general guidance, not legal advice. Levy rates are indexed annually and the Regulations are amended often, so check the current rate summary and the consolidated Regulations, and confirm the position with your charging authority before relying on any figure.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.