Tracking CIL and S106 Together: Why Developer Contributions Need One System

A single development can carry a Community Infrastructure Levy liability, a Section 106 obligation, a clutch of dated notices, and a clawback period that runs for years after completion. Run a portfolio of schemes across several authorities and the number of moving parts multiplies fast. The cost of losing track is not abstract: a missed CIL Commencement Notice can forfeit instalments and trigger a surcharge; a missed S106 trigger point can put a developer in breach.

This post makes the case for tracking developer contributions — CIL and S106 — in one system rather than scattered spreadsheets, and sets out what that system needs to capture.

This covers England only. This is general guidance, not legal advice.

Two Mechanisms, One Scheme

CIL and Section 106 are different instruments with different rules, but they land on the same development:

• The Community Infrastructure Levy is a fixed, formula-based charge set by the charging schedule. It comes with a notice sequence — assumption of liability, commencement notice, demand notice — and dated payment instalments. See our developer's guide to CIL.
• The Section 106 obligation is a negotiated, site-specific agreement — affordable housing, financial contributions tied to trigger points, highways works, and more. See our guide to how S106 developer contributions work.

A developer who tracks one but not the other has only half the picture. The CIL instalment due dates and the S106 trigger points both sit on the same scheme programme, and both carry consequences if missed.

What Gets Lost in Spreadsheets

The default for most developers and consultants is a spreadsheet — often one per scheme, sometimes one per person. The failure modes are predictable:

• Notice deadlines fall through the gaps. The CIL Commencement Notice has to be in before work starts on each scheme. When attention is on the scheme that is mobilising this week, the one starting next month is easy to forget — and the consequence is the full charge falling due plus a surcharge.
• Clawback periods get forgotten. A self-build CIL exemption runs a three-year clawback; a disqualifying event needs notifying within 14 days. Three years is a long time for a spreadsheet row to survive a change of staff or a folder reorganisation.
• S106 trigger points are buried in the deed. "On occupation of the 50th dwelling" or "prior to commencement of phase 2" — these are easy to write into an agreement and easy to miss in delivery, especially across phased schemes.
• No single view across the portfolio. When each scheme lives in its own file, no one can answer "what contributions are due in the next quarter across all our sites?" without rebuilding the picture by hand.
• Version drift. A deed of variation changes the obligation; if the spreadsheet still shows the original terms, the developer is tracking the wrong thing. See our guide to deeds of variation.

None of these is exotic. They are the routine ways a contribution obligation gets missed — and each one is avoidable with a structured record.

What a Single System Needs to Capture

Whether it is a well-built spreadsheet or a purpose-made tool, tracking developer contributions properly means capturing, for every scheme:

For CIL:

• The chargeable amount and how it was calculated (rate, floorspace, indexation).
• Assumption-of-liability status and date.
• The Commencement Notice deadline and submitted date.
• Reliefs or exemptions claimed, and any clawback expiry date.
• Instalment due dates and payment status.

For Section 106:

• Each obligation and its type (financial, in-kind, restrictive).
• The trigger point for each obligation, in plain terms.
• For financial contributions: the indexed amount, due date, and any spend-by deadline on the council side.
• Variation history — which obligations were modified, when, and by which deed.

Across both:

• The charging authority for each scheme.
• A forward view of every deadline due in the coming weeks and months.
• A clear audit trail of what was submitted, when, and by whom.

Why This Matters More After the 2019 Reforms

The 2019 amendments to the CIL Regulations removed the old Regulation 123 restriction on pooling Section 106 contributions, and authorities now publish annual Infrastructure Funding Statements showing what they fund through CIL and S106 together. The practical effect for developers is that CIL and S106 are increasingly managed as a single contributions picture by authorities — and a developer whose own records keep them separate is working against the grain. Tracking them together mirrors how the obligations are actually administered.

The Case for Purpose-Built Tracking

A spreadsheet works for one scheme. It strains at a portfolio, and it has no way to warn you that a Commencement Notice is due next week or a clawback period expires next month. As the number of schemes grows, the value shifts from recording obligations to being alerted to them before the deadline.

S106Ledger is being built for exactly this: a single record of developer contributions — CIL and S106 — across a portfolio, with the notice deadlines, trigger points, and clawback periods tracked in one place rather than scattered across files. It is not live yet; if managing contributions across multiple schemes is a problem you recognise, you can join the waitlist to hear when it is ready.

Summary

A single development carries both a CIL liability and, often, a Section 106 obligation — each with its own dated notices, trigger points, and clawback periods. Managed in scattered spreadsheets, those deadlines get missed, and the cost of a missed CIL Commencement Notice or S106 trigger is real. Tracking developer contributions in one system — capturing the calculation, the notices, the trigger points, and a forward view of every deadline — is what keeps a portfolio of schemes from slipping. As authorities increasingly manage CIL and S106 as one contributions picture, developers benefit from doing the same.

Sources

• Community Infrastructure Levy Regulations 2010 (SI 2010/948)
• Town and Country Planning Act 1990, Section 106
• GOV.UK — Community Infrastructure Levy guidance