Self-build and custom build duties on larger sites
Plot requirements on larger sites come from the register duty in the 2015 Act. What serviced means, how to draft the marketing obligation and where CIL bites.
A self build plots policy requirement on a larger site comes from a statutory duty that has nothing to do with housing mix policy. The Self-build and Custom Housebuilding Act 2015 makes every relevant authority keep a register of individuals and associations seeking serviced plots, and requires it to give enough suitable development permission to meet the demand that register shows. Local plans then translate that duty into a percentage of plots on sites above a stated threshold. If your site is caught, the requirement is a plot delivery obligation rather than a housing tenure one.
Check the adopted plan first, because the threshold and the percentage are entirely local and vary widely.
The register duty and what it produces
Section 1 of the 2015 Act creates the register. Individuals and associations who want to acquire a serviced plot to build or commission their own home apply to the authority, and the authority must enter those who meet the eligibility conditions in the Self-build and Custom Housebuilding Regulations 2016.
Those Regulations allow an authority to impose a local connection test and a financial solvency test, and to charge a fee for entry and renewal. Many authorities run two parts to the register: those meeting the local tests, who count towards the duty, and those who do not.
The duty that follows is in section 2A. The authority must give suitable development permission for enough serviced plots to meet the demand on the register in each base period, within three years of the end of that base period. Base periods run annually, ending on 30 October. The Levelling-up and Regeneration Act 2023 strengthened the framework, requiring authorities to have regard to the register when exercising their planning functions and to publish more about how they are meeting the duty.
What this produces on the ground is an authority with a number it has to satisfy and few sites on which to satisfy it. Larger applications are where it looks.
Policies requiring serviced plots on larger sites
Local plan policies take one of three shapes.
- A percentage of dwellings on sites above a threshold to be provided as serviced self build plots.
- A fixed number of plots on allocated sites, written into the site allocation itself.
- A requirement to offer plots, with a fallback allowing them to revert to conventional dwellings if unsold after a marketing period.
The third is the most common and the most negotiable. Read the policy for four things: the site size threshold, the percentage or number, the marketing period, and what happens to unsold plots. A policy silent on reversion is a policy that leaves a developer holding plots indefinitely, and that is worth raising at examination or in negotiation.
A plot requirement affects the housing mix and space standards as a scheme grows, because plots are usually detached, take more land per unit and sit at the edge of the layout.
Plot specification and servicing expectations
Serviced has a statutory meaning. Under the 2015 Act a serviced plot is land that has access to a public highway and has connections for electricity, water and waste water, or can be provided with those within a stated period.
In practice authorities and buyers expect more, and the specification is worth agreeing in the application rather than in the agreement.
| Element | Usual expectation |
|---|---|
| Access | Adopted or adoptable road frontage, with a dropped kerb or bellmouth built |
| Utilities | Electricity, water and foul drainage connections to the plot boundary, capped and marked |
| Surface water | Plot connection to the estate drainage, with a stated discharge allowance |
| Levels | Plot cleared, levelled and topsoiled, with a datum recorded |
| Boundaries | Boundaries defined on the ground and in the transfer plan |
| Design control | A plot passport or design code, with the parameters the buyer must work within |
The plot passport is the document that makes or breaks buyer confidence. A single sheet giving the building zone, the maximum height and ridge line, the acceptable materials palette and the parking requirement lets a buyer instruct an architect without a second planning application. Without it, every plot becomes a reserved matters negotiation.
Marketing periods and fallback provisions
The marketing obligation is where most agreements are argued over. Four points need to be nailed down.
- Duration. Commonly a period running from practical completion of the plot servicing, and the trigger point matters more than the length.
- Method. Listing with agents, notification to everyone on the relevant part of the register, a dedicated web page, and a price basis.
- Price. A requirement to market at a price reflecting open market value, evidenced by a valuation, rather than at whatever the developer chooses.
- Reversion. What the developer may do if plots do not sell: build them out conventionally, or hold and remarket.
Tie the marketing trigger to servicing completion, not to the start of the phase. A marketing period that runs while the plot is a muddy field with no access produces no sales and satisfies nobody.
Interaction with affordable housing obligations
Self build plots are market housing. They do not count towards an affordable housing requirement and they do not reduce it, so the affordable housing statement still addresses the scheme's full obligation.
Two financial interactions are worth modelling early. Plots sell as land rather than as completed homes, so the revenue profile and the timing differ from the rest of the scheme. And a self builder occupying the finished dwelling as their sole or main residence can claim the self build exemption from the Community Infrastructure Levy under the CIL Regulations 2010, which reduces the levy the site generates. The procedure is exacting: the exemption has to be claimed before development starts and a commencement notice served, with a three year clawback period.
That second point cuts both ways. It helps the buyer and it reduces the infrastructure income the authority was counting on, which is an argument to make when a plot requirement is being pressed alongside a heavy obligations package. Energy and carbon requirements scale in the same stepped way, and the evidence expected as a residential scheme grows is worth mapping against the plot phasing.
Securing plots in a legal agreement
The obligation sits in the section 106. Drafting points that repay attention:
- Identify plots on a plan, with numbers and areas, rather than by a percentage.
- Define the servicing standard by reference to a specification appended to the agreement.
- Set the marketing trigger, duration, method and price basis.
- Set out the reversion mechanism and any notification the authority must receive before it operates.
- Restrict disposal to a person who will build or commission the dwelling, and prevent aggregation of plots by a single housebuilder.
- Keep occupancy obligations light. A requirement to complete within a fixed period is reasonable, and an obligation policing who lives there afterwards is not enforceable in practice.
Illustrative example: a 96 dwelling allocated site with a policy seeking five per cent serviced plots. Five plots identified on the layout at the edge of the site with direct frontage onto an adoptable spur, serviced to boundary, plot passports issued with the reserved matters approval, marketed for 12 months from servicing completion with notification to the authority's register, reverting to conventional units if unsold. Two sold in the first six months.
Evidence of demand from the register
Where you want to resist or reduce a plot requirement, the register is the evidence to interrogate rather than the policy.
Ask the authority for the published register figures, including the split between applicants who meet the local connection test and those who do not, and the number of plot permissions the authority has already granted in the relevant base periods. An authority that has already met its duty through other permissions has a weaker case for loading the requirement onto your site.
Ask also about location. Register demand concentrated in one part of a district is not evidence of demand at your site, and a policy applied uniformly across an authority area rarely reflects where self builders want to be.
Enter your postcode on PlanScope to see which reports a larger residential site is likely to need, then send the drafts for professional review.
This is general guidance, not legal advice. Plot requirements and register duties are applied locally, so check the adopted plan and take advice from a planning professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
What is a serviced plot?
Under the Self-build and Custom Housebuilding Act 2015 it is land with access to a public highway and connections for electricity, water and waste water, or land that can be provided with those within a stated period. Buyers and authorities usually expect more: a built access, capped connections at the boundary, a cleared and levelled plot and a plot passport.
Where does the duty on councils come from?
Section 1 of the 2015 Act requires a register of people seeking serviced plots, and section 2A requires the authority to give suitable development permission for enough plots to meet the demand on that register in each base period, within three years of the end of it. Base periods run annually, ending on 30 October.
Do self build plots count towards affordable housing?
No. Self build plots are market housing, so the affordable housing requirement applies to the scheme in full and the plots neither count towards it nor reduce it. Model the revenue profile separately too, because plots sell as serviced land rather than as completed dwellings and the cash flow timing differs.
How does CIL work on a self build plot?
A self builder who will occupy the completed dwelling as their sole or main residence can claim the self build exemption under the Community Infrastructure Levy Regulations 2010. The procedure is strict: claim before development starts, serve a commencement notice, and hold the exemption through a three year clawback period. It reduces the levy income the site generates.
What happens to plots that do not sell?
That depends on the reversion provision in the section 106. Most agreements allow unsold plots to be built out conventionally after a marketing period, subject to notifying the authority. Tie the marketing trigger to completion of the plot servicing rather than to the start of the phase, because marketing an unserviced field produces no sales.
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.