Every development appraisal carries two costs that don't appear on any sales brochure: Section 106 obligations and the Community Infrastructure Levy. Both are legally attached to the site or the permission, both bite the cashflow at defined trigger points, and both are checkable before you commit — if you know where to look. This guide walks the checking process step by step, using official sources, and finishes with what a lender expects to see once you've done it.
Section 106 obligations and CIL are different instruments and are checked in different places. S106 is a negotiated agreement specific to a permission; CIL is a fixed charge set by a published schedule. Check both — a site can carry either, both, or neither.
Step 1: Find the Section 106 agreement
Start at the local planning authority's online planning register. Search the site address or the planning reference, open the application that granted permission, and look in the documents list for the agreement — usually filed as "S106 Agreement," "Legal Agreement," or "Unilateral Undertaking," typically dated at or just before the decision notice.
If it isn't published — and many aren't, especially on older permissions — two routes remain. A local land charges search (LLC1) will reveal the agreement, because S106 obligations are registered as local land charges against the land. Or request it directly from the LPA's planning department; it's a public document and they must provide it.
One check people miss: obligations run with the land, not the applicant. An agreement signed under a previous permission, or by a previous owner, can still bind the site. Search the full planning history, not just the live consent.
Step 2: Read what the agreement actually obliges
An S106 agreement is a deed, and the substance lives in the schedules at the back, not the recitals at the front. Work through them for:
Financial contributions — education, highways, open space, healthcare. Note each sum, and note it per what: per dwelling, per square metre, or as a lump sum.
Trigger points — when each payment falls due. "On commencement," "on occupation of the 10th dwelling," "prior to first occupation." Triggers determine where the cost lands in your cashflow, which is what a lender models.
Indexation — almost every agreement indexes contributions from the date of the agreement to the date of payment, commonly against BCIS or CPI. A £200,000 obligation in a 2019 agreement is not £200,000 today. Calculate the indexed figure; the headline number understates the liability.
Affordable housing — the percentage, the tenure split, and whether there's a review mechanism or a viability clause that could move it.
Restrictions — occupancy restrictions, local connection requirements, clawback provisions. These affect GDV, not just cost.
Step 3: Check for modifications
Agreements get varied. Look in the planning history for deeds of variation and for applications under Section 106A (modification or discharge of obligations). A viability renegotiation after the original consent can materially change the affordable housing requirement or contribution levels — in either direction. The agreement you found in Step 1 is only the current position if nothing came after it.
Step 4: Establish CIL liability
CIL is checked against publications, not negotiated documents.
First: is the local authority a CIL charging authority at all? Not every LPA in England charges CIL. The authority's website will have a CIL page stating whether a charging schedule is in force.
If it is, find the charging schedule — a published document setting rates in £ per square metre, usually varying by development type and by zone within the authority's area. The applicable rate is the one in force when permission was granted, indexed forward. Charging schedules get revised, so match the schedule to the permission date.
Then apply the mechanics: CIL is charged on net additional floorspace (gross internal area), with existing in-use floorspace deductible under defined conditions. The authority's Liability Notice, if one has been issued, states the calculated amount — ask for it if you're buying a consented site.
Step 5: Check reliefs — and the traps around them
Relief exists for affordable housing, charities, and self-build, but every relief has procedural conditions. The one that catches people: commencing development before submitting a Commencement Notice. Since September 2019 that no longer automatically forfeits the relief — instead the collecting authority must impose a surcharge of 20% of the notional chargeable amount, capped at £2,500. Relief can still be lost for other process failures (for example commencing before the claim is decided, or a disqualifying event in the clawback period). On a consented site someone else started, verify what notices were served and when. A relief the seller assumed can be a liability the buyer inherits.
Step 6: Cross-check against the authority's own reporting
Charging authorities publish annual Infrastructure Funding Statements setting out what they've collected and secured through CIL and S106. For a sense-check on how an authority actually applies its policies — typical contribution levels, how much S106 it secures per scheme — the IFS is the official record. It won't give you your site's number, but it will tell you whether your estimate is in the authority's normal range.
Step 7: What a lender needs to see
A lender doesn't want to know that you checked — it wants the results in a form a credit analyst can verify:
- Each S106 obligation itemised, with its trigger, its indexation basis, and the indexed current figure
- CIL liability calculated against the named charging schedule, with the rate, the chargeable area, and any relief position stated
- Source references for every figure — the agreement clause, the schedule, the liability notice
Set out that way, obligations stop being a diligence question and become a line in the appraisal. Left out, they surface as a further-information request three weeks into underwriting — the expensive way to learn a number you could have had on day one.
This is the standard a lender-ready credit pack is built to. PlanSureAI produces the S106 and CIL position — costed, indexed, and source-referenced — as part of the pack it generates from a site address. If you have an agreement in hand and want the obligations extracted now, the S106 Analyser does it free.
Frequently asked questions
Can a site have both Section 106 obligations and CIL liability?
Yes, and consented sites in charging authorities usually do. CIL funds general infrastructure; S106 addresses site-specific impacts. Check both independently.
Do S106 obligations expire?
No — they bind the land until discharged or modified. Obligations more than five years old can be applied to be modified under Section 106A, but until varied, they stand as written.
Who pays if the site is sold?
The obligations run with the land. Liability for CIL can be transferred by notice; S106 obligations bind successors in title automatically. Price them into the land, because the buyer inherits them.
Is CIL negotiable?
No. Unlike S106, CIL is a fixed charge under the published schedule. The only levers are reliefs, exemptions, and getting the floorspace calculation right.