Worked open space contribution from an adopted standard

An open space contribution calculation runs in four steps: find the adopted standard, convert your dwelling mix into people, convert people into square metres, then price the square metres for provision and for maintenance. Every step uses a figure the council has published, and every figure is arguable if it has not. A self-builder putting six houses on a site should be able to produce the whole calculation on one page and check the council's demand against it.

What follows works through that page. The rates used at the costing stage are illustrative placeholders, not real figures from any authority, and the actual rates come from the council's own supplementary planning document.

Finding the adopted standard and its units

Start with the adopted local plan, then the open space or planning obligations supplementary planning document, then any published contributions schedule. You are looking for three things: the quantity standard, the typology it is split into, and the accessibility standard.

Quantity standards are normally expressed in hectares per thousand population, and they are almost always split by type: outdoor sport, equipped play, informal or amenity greenspace, allotments and sometimes natural greenspace. A widely cited benchmark used by many authorities allocates 1.6 hectares per thousand to outdoor sport and 0.8 hectares per thousand to children's play, giving 2.4 hectares in total, but the adopted figure is whatever your council has adopted and that is the only one that counts.

The accessibility standard matters as much as the quantity. A council that requires equipped play within 400 metres walking distance of every dwelling is telling you whether on-site provision is expected or whether a payment towards an existing facility is acceptable.

Note the base date of the standard and whether the evidence behind it is a current open space assessment. A standard drawn from an audit that is a decade old is still adopted policy, but its application to your site can be questioned where the audit shows surpluses that no longer exist.

Deriving occupancy from the dwelling mix

Contributions are based on people, not units. Councils publish occupancy assumptions by bedroom count, usually derived from census household size data for their own area.

The figures below are an illustrative set of the kind published in supplementary planning documents. Use your council's own table.

Two adjustments come up. Where the scheme replaces existing dwellings, the occupancy of what is lost is normally deducted, so a net figure applies. And where a unit is age restricted or has a occupancy condition, councils will sometimes apply a lower figure, although many refuse on the basis that the condition can be varied later.

Check whether the council's threshold catches your scheme at all. Many authorities set a minimum size below which no open space contribution is sought, and the threshold is often expressed in units rather than in floorspace.

Converting need into area

The arithmetic is direct. Population multiplied by the standard, divided by a thousand, gives hectares. Convert to square metres by multiplying by ten thousand, because contributions are almost always priced per square metre.

Do it separately for each typology, because the rates differ and because the delivery route differs. Equipped play is frequently provided on site on a scheme of any size. Outdoor sport almost never is, because a pitch needs more land than a small site has, so it converts into a payment towards an existing or planned facility.

Where the council expects on-site provision and the site cannot accommodate it, say so with a plan rather than in prose. An officer needs to see that the required area would consume the parking court or breach the separation distances before agreeing to a commuted payment.

Costing provision and maintenance

Two numbers are needed for each typology: a capital rate for creating the space and a maintenance rate for keeping it.

Capital rates come from the council's schedule and are usually per square metre, sometimes with a separate item per piece of play equipment. Maintenance is normally a commuted sum, calculated as an annual rate per square metre multiplied by a defined period, commonly ten, fifteen or twenty years. Check the period, because doubling it doubles that part of the bill.

Where the space is transferred to the council, the commuted sum is the price of adoption. Where it stays in private management, the sum is not payable but a management company and a deed are needed instead, and the appraisal should carry the setup cost and the risk of future adoption requests. The choice belongs in the viability appraisal inputs schedule alongside the other section 106 items.

Checking the sum against the obligation tests

A contribution must satisfy the three tests in regulation 122 of the Community Infrastructure Levy Regulations 2010: necessary to make the development acceptable in planning terms, directly related to the development, and fairly and reasonably related in scale and kind to it.

Three challenges follow from those words.

Is the facility identified? A payment into a general fund with no named project is harder to justify as necessary and directly related than a payment towards a specific, identified scheme. Ask what the money will be spent on.

Is the scale right? A contribution towards a facility two miles away that your residents will not realistically use fails the directly related test.

And is there double counting with the Community Infrastructure Levy? Where the authority charges the levy and lists open space among the infrastructure it funds, a separate section 106 payment for the same thing invites a challenge. Authorities publish infrastructure funding statements showing what has been collected and spent, so read the relevant one before accepting a demand.

Triggers, indexation and what happens if the scheme changes

Fix the payment trigger in the heads of terms. On a small scheme, payment before first occupation is common, and payment on commencement is worse for cash flow. Where the scheme is phased, tie the payment to the phase.

Indexation is normal and reasonable. Check the index named, the base date, and whether indexation runs from the date of the agreement or the date of the adopted schedule. A sum indexed from a base date five years earlier is materially larger than the headline figure.

Ask for two protections. A clawback or repayment clause if the money is unspent after a defined period, commonly five or ten years, and a mechanism to recalculate if the dwelling mix changes on a later section 73 application. Without the second, adding a bedroom to one plot can mean renegotiating the whole agreement.

Illustrative figures for six dwellings

All figures in this section are illustrative. They are not taken from any authority's adopted schedule.

Mix: two two-bedroom houses, three three-bedroom houses, one four-bedroom house. Applying the illustrative occupancy table gives (2 x 2.0) + (3 x 2.6) + (1 x 3.2), which is 15.0 persons.

Applying an illustrative standard of 0.8 hectares per thousand for equipped play gives 15.0 divided by 1,000, multiplied by 0.8 hectares, which is 0.012 hectares or 120 m². The same calculation at 1.6 hectares per thousand for outdoor sport gives 240 m².

Costing at an illustrative capital rate of £75 per m² for play space produces £9,000, and a commuted maintenance sum at an illustrative £3.50 per m² per year over 15 years produces £6,300. Outdoor sport converts to an off-site payment at an illustrative £45 per m², which is £10,800.

The total is £26,100, plus indexation from the base date, which is around £4,350 per dwelling. On a six unit scheme that number is large enough to change the land bid, which is why it belongs in the appraisal before the offer rather than after the resolution to grant.

The method is the point rather than the numbers. Substitute your council's occupancy table, standards and rates and the structure holds. The same discipline of showing every input applies to drainage work, as in the worked greenfield run-off rate for a 0.6 hectare site.

Where a formal assessment is expected, PlanScope drafts an Open Space Assessment or a Play Space Assessment from your site and mix details, flagging the figures it does not have rather than inventing them. Enter your postcode on PlanScope to see which documents a small residential scheme is likely to need.

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.