Planning Agreements & Obligations

Getting planning permission is not always the end of it. Many developments need one or more separate legal agreements before they can actually be built – and they are made under different Acts, with different bodies, on different timescales. A smaller development may need none of them at all. None of them is your planning application.

This page explains which is which, and which one you are likely to need. If you are looking at the wider package of affordable housing, infrastructure and developer contributions secured through planning, see our guide to planning gain.

The main agreements and obligations, and what each is for

Several Acts and several organisations are involved. The quickest way to tell them apart is to ask what the agreement or obligation is about.

• Section 106 – a planning obligation. Affordable housing, contributions, biodiversity. Made with your council, under the Town and Country Planning Act 1990. It binds the land. If an old obligation is causing a problem, see how to modify or discharge an old Section 106 agreement
• Unilateral undertaking – the same obligation, given by you alone without the council signing. Quick to give, slow to undo, and the usual route at appeal
• Conservation covenant – a private conservation obligation under the Environment Act 2021. Made with a responsible body, not the council, and needing no planning permission. It binds the land, often indefinitely
• Section 278 – works to the road that is already there. The junction, the signals, the right-turn lane. Made with the highway authority, under the Highways Act 1980
• Section 38 – adoption of the new road you are building. Made with the highway authority, under the Highways Act 1980
• Section 104 – adoption of new sewers, agreed before you build them. Made with your water company, under the Water Industry Act 1991
• Section 102 – adoption of sewers that already exist. An existing-sewer adoption route, often considered where no completed Section 104 agreement is in place. Dealt with by the relevant sewerage undertaker

Which will my development need?

A rough guide, and no substitute for asking.

• A single house on an existing road – possibly none of them. You may need a Section 184 for a dropped kerb, and a sewer connection, but that is a different scale of problem
• A small scheme with a new access – a Section 278 for the access. Maybe a Section 106, depending on your council and what the scheme triggers
• A housing estate – likely to need several of them, depending on the obligations and infrastructure involved. A Section 106 for obligations, a Section 278 where you meet the existing road, a Section 38 for the estate roads, a Section 104 for the drainage

The pattern worth noticing: the bigger the scheme, the more separate bodies you are negotiating with, and none of them is waiting for the others. A Section 278 and a Section 104 can be running at the same time with different teams, and both can hold up a start on site.

Two things that catch people out

They are often not optional. A planning condition or a Section 106 will frequently require the highway or drainage agreements to be in place before you start, or before anyone moves in. So the agreement is not an administrative afterthought – it is the mechanism by which your permission becomes buildable. A permission that looks granted can sit unimplementable for months.

There are two Section 106s. Section 106 of the Town and Country Planning Act 1990 is a planning obligation, made with your council. Section 106 of the Water Industry Act 1991 is a sewer connection, made with your water company. Same number, different Acts, nothing in common. If someone tells you that you need “a section 106”, find out which.

Costs

Every one of these agreements costs money, and none of it is your planning application fee, which is separate and separately payable.

We do not publish figures on these pages because there are no national rates. Each highway authority sets and revises its own charges for Sections 38 and 278, while each sewerage undertaker publishes its own Section 104 charges and requirements. A figure found on another authority’s page, or copied from an old schedule, may not apply to your scheme. Ask the relevant body for its current position, in writing, at an early stage.

What you can plan for is the shape: the works themselves, a bond or surety, the authority’s own costs including staff time, and often a commuted sum towards future maintenance.

Help us expand this section

We will add to this list in due course. If you would like to help write any of these sections, please contact us – we are happy to include a credit and a link to your company.

Developer contributions & planning agreements

Planning Agreements Page Updated: 25th August 2026