Catchment and capacity in a social infrastructure assessment

The catchment and capacity section is where a Social Infrastructure Assessment either supports a contribution figure or invites the authority to invent one. Its job is narrow: define a realistic catchment for each facility the scheme will draw on, set out the published capacity of the facilities inside that catchment, and compare both against the demand your housing mix generates. Get that sequence right and the negotiation over school, health and community contributions becomes arithmetic. Get it wrong and the council's own figures fill the gap.

Defining catchments for each facility type

There is no single catchment radius, and a report that applies one to everything reads as a template. Each facility type has its own geography, and you should say where yours comes from.

Primary education is usually assessed on walking distance, with the statutory walking distances in section 444 of the Education Act 1996 as the backstop: two miles for children under eight and three miles for children of eight and over. Secondary education works on a wider travel-to-learn area, often the whole authority or a defined planning area. Health is governed by practice boundaries rather than distance, because a surgery can decline registration outside its published area. Sports facilities and open space are commonly assessed against the standards in the adopted local plan or a playing pitch strategy prepared to Sport England's methodology.

Community halls, libraries and places of worship rarely have a formal catchment at all. For those, use the authority's own adopted standard where one exists and say plainly when it does not.

Obtaining published capacity data

Capacity evidence has to be traceable. For schools, the authority's own place planning report or school organisation plan gives net capacity and forecast rolls by planning area, and the data returned to central government through the annual capacity survey sits behind it. For health, the commissioning body publishes registered list sizes and practice numbers. For sports provision, the playing pitch strategy and facility audits give quantity and quality.

Three rules save arguments later. Cite the document, its date and the planning area or practice you took the figure from. Use the latest published version rather than the one quoted in an earlier application. And where the data is a forecast, state the forecast year, because a roll projection for 2029 says nothing useful about a scheme completing in 2033.

Where a figure is not published at all, say so and describe what you did instead. An honest gap in the evidence base is easier to defend than an unsourced number.

Calculating demand from the housing mix

Demand comes from the schedule of accommodation, not from the unit count. Most authorities publish pupil product ratios by bedroom number, and the difference between a scheme of one and two-bedroom flats and one of three and four-bedroom houses is large enough to change the contribution by a full form of entry on a bigger site. Use the authority's own published multiplier where it has one. Where it does not, use the county or regional figure and name it.

The same discipline applies to health, where demand is expressed as additional registered patients, and to open space, where it is expressed in square metres or hectares per thousand population using the local plan standard. Occupancy assumptions should be stated once, in a table, and used consistently across every facility type in the report.

Affordable and market tenures generate different household sizes in most published datasets. If the authority's multipliers distinguish them, apply that distinction rather than averaging it away.

Distinguishing capacity from convenience

This is the section that decides the negotiation. A school two miles away with 40 surplus places has capacity. Parents may not like it, and the ward councillor may say so at committee, but a contribution cannot be justified on preference alone.

Regulation 122 of the Community Infrastructure Levy Regulations 2010 requires an obligation to be necessary to make the development acceptable, directly related to it, and fairly and reasonably related in scale and kind. A request that funds a facility the scheme does not measurably burden fails the first test. Say so in the report, politely, with the capacity figures underneath. The Planning Practice Guidance on planning obligations is the reference to quote when you do.

Where there is no capacity at all, be equally direct. Understating a shortfall to reduce a contribution tends to produce a refusal on infrastructure grounds and a longer, more expensive route to the same number.

Linking findings to contribution requests

Each finding should end in one of three conclusions: existing capacity absorbs the demand, a financial contribution is justified for a stated purpose, or on-site provision is required. Set out which facility, which shortfall, and which mechanism, and cross-refer to the draft heads of terms.

Keep the calculation visible. A contribution built from a pupil yield, a cost multiplier and a published capacity figure can be checked in two minutes by the officer, and officers approve what they can check. Buried arithmetic gets replaced by the council's own standard charge.

This is also where the evidence in an assessment meets the evidence in a viability case. If the total obligation package is unaffordable, the capacity work still needs to be right, because the viability assessment argues about what can be paid, not about what is needed.

Phasing provision with occupation

On any scheme delivered over several years, the section should set out when each pressure arrives. School places are needed when families move in, not at first occupation of the first block, and a phased trigger tied to occupation numbers is easier to agree than a single payment on implementation.

Set out the triggers you propose:

1. The occupation number or phase at which each payment falls due.
2. The indexation basis, which is normally a published construction cost index.
3. The period after which unspent money is returned.
4. Any land transfer, with the timing tied to a stage the authority can monitor.

Councils increasingly publish what they collected and spent, so the return clause and the monitoring arrangements are worth agreeing carefully. The drafting habits are the same ones that make a supply chapter work: the supply chapter of an employment land assessment faces the identical problem of turning published stock data into a defensible conclusion. Where the scheme raises equality questions as well, the evidence for protected characteristics in an equalities impact assessment draws on the same population figures.

Presenting the evidence for negotiation

Structure the section so it can be lifted into an officer report. One table per facility type, with columns for the facility, the catchment and its source, the published capacity and its date, the demand your scheme generates, and the resulting conclusion. Then a short paragraph of narrative under each table explaining the judgement, not restating the numbers.

An illustrative example

A 120-dwelling scheme on the edge of a market town, mixed houses and flats. Applying the county's published pupil product ratio produces roughly 30 primary and 18 secondary pupils. The place planning report shows 55 surplus primary places in the planning area but a secondary forecast in deficit from the third year of the build programme. The assessment concludes no primary contribution, a secondary contribution phased to the 60th and 100th occupations, and a health contribution based on the registered list position at the two practices whose boundaries cover the site. This example is illustrative, not a real decision.

Write the limitations down as you go. Where a forecast is older than a year, where a practice boundary is unclear, or where the authority has no adopted standard for a facility type, a sentence saying so protects the conclusion. A draft can be produced quickly and structured to UK planning policy, then checked by whoever will defend it at committee.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified 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. Browse all 66 PlanScope report types and start a draft.