Open space contributions by dwelling count

An open space contribution per dwelling is almost never a flat figure per house. Local plan policies convert the number and size of dwellings into a projected population, apply a quantity standard per thousand people, and then ask either for that area on site or for a payment towards provision elsewhere. The arithmetic matters because the answer changes shape at the point where the calculated area becomes big enough to be a usable park rather than a mown triangle nobody visits.

Which means the first thing to work out is not the money. It is the population your scheme is assumed to generate.

How requirements are expressed per dwelling or per person

Most adopted policies work in three steps. An occupancy assumption converts bedrooms into people, usually drawn from census household size data for the area. The projected population is multiplied by a quantity standard expressed as hectares per thousand population, broken down by typology. The resulting area is then either provided on site or converted to a sum using a cost per square metre for laying out and equipping that typology.

The typologies are where the detail lives. A policy will separate parks and gardens, natural and semi-natural greenspace, amenity greenspace, provision for children and young people, outdoor sports facilities and allotments, each with its own standard. A scheme of flats with no family housing may generate a large requirement for amenity greenspace and almost none for equipped play.

The historic benchmark behind many of these standards is the old National Playing Fields Association figure of six acres, about 2.4 ha, per thousand population for outdoor playing space. National guidance now expects authorities to set their own standards from an assessment of local need rather than adopting a national figure, so read the standard in the adopted plan and the open space study that sits behind it. Where the plan is old and the study older, the figures may be the only thing in the policy that is still arguable.

On-site provision against commuted sums

The policy usually sets a threshold at which on-site provision is required rather than optional. Below it, a payment towards off-site provision is accepted. Above it, the authority wants the space on the ground.

Those bands are indicative of how policies are commonly structured rather than a national rule, and the figures in your plan will differ. What is consistent is the logic: small schemes pay, large schemes build, and the middle is negotiated.

A commuted sum has to satisfy the statutory tests for planning obligations. It must be necessary to make the development acceptable, directly related to the development, and fairly and reasonably related in scale and kind. Since the pooling restriction was lifted in 2019 an authority may collect from multiple schemes towards one project, but it still has to identify the project and show the connection. Ask which facility the money is for and what it will buy, and ask it in writing at the heads of terms stage rather than after the resolution to grant.

Quantity, quality and accessibility standards

Quantity is the easiest to meet and the least useful on its own. Authorities that have done the work set quality and accessibility standards alongside it, and those are what decide whether your on-site provision counts.

Accessibility is usually distance based. Natural England's accessible natural greenspace guidance is the most widely quoted framework, with a benchmark of at least 2 ha of accessible natural greenspace within 300 m of home, larger sites within 2 km and beyond. Local policies translate that into walking distances to each typology, measured along routes rather than as the crow flies. A 0.4 ha green at the back of the site, reached only through a parking court, may fail an accessibility standard it appears to satisfy on a plan.

Quality standards tend to reference a published site assessment methodology and a scoring system. Where the policy allows a contribution towards improving an existing park instead of new provision, the quality score of that park is the justification, and an Open Space Assessment that audits the existing provision against the standard is what demonstrates the deficiency the money will address.

Sport England is a statutory consultee where a scheme affects a playing field, and that consultation runs on its own policy tests regardless of what the open space calculation says.

Where provision becomes viable on site

Small areas of open space are a liability rather than an asset, and experienced officers know it. Below roughly a tenth of a hectare, a piece of amenity greenspace is a maintenance cost with no recreational function, and it tends to attract antisocial use and fly-tipping.

The practical questions for a given scheme:

1. Does the calculated area reach a size that can hold a function, such as a kickabout, a toddler play area with a buffer to the nearest habitable window, or a planted swale with a path?
2. Can it be overlooked by homes on at least two sides, which is what makes it usable after dark in winter?
3. Does it double as something else without compromising either use, such as surface water attenuation shaped as a shallow basin with a mown edge?
4. Who maintains it, and is that arrangement funded for the long term?
5. Does it take developable frontage, and if so is the land value lost greater than the commuted sum avoided?

Answer those honestly and the choice between on-site provision and a payment usually makes itself. Where the scheme comes forward in phases, the sequencing of provision has to be written so that early occupiers are not waiting on a park delivered in phase four, and the guidance on phasing a large scheme without gaming thresholds covers how authorities police that.

Maintenance and management responsibility

Three models, each with a different price.

Adoption by the local authority with a commuted maintenance payment, usually calculated as a number of years of maintenance cost. The figure is often the largest single open space line in the agreement, and the number of years is negotiable in a way the capital cost is not.

A management company funded by estate charges on the homeowners. Lower cost to the developer at the point of sale, increasingly unpopular with purchasers and lenders, and the subject of growing policy attention. Expect questions about the charge level, the transparency of the accounts and the arrangements if the company fails.

Transfer to a parish council or a land trust, with an endowment. Workable on larger schemes and attractive where there is an existing body with capacity, but it needs the recipient to agree before the application is determined rather than afterwards.

Whichever model, the agreement should fix the specification to be delivered, the condition at transfer, a defects period, and what happens if the space is not completed by the occupation trigger.

Interaction with play space and biodiversity

Play space is usually a separate calculation driven by child yield rather than total population. In London the standard is 10 m² of play space per child, with the child yield derived from the authority's population yield assumptions, and provision expected for different age groups at different distances from home. A Play Space Assessment sets out the yield, the provision by age group and the distances.

Biodiversity net gain overlaps awkwardly with open space. Amenity grassland scores poorly in the statutory metric, so a scheme that meets its open space quantity with mown grass may still be short of habitat units. Designing the same land as species diverse grassland with scrub edges and trees can deliver both, but it then has to be managed for thirty years to that specification, and the maintenance regime the authority adopts for an amenity green will not do it.

That tension is worth resolving at layout stage with the ecologist and the landscape designer in the same conversation. A Green Infrastructure Plan is the document that holds the two together, and councils usually expect a suitably qualified author for the habitat elements, with professional review strongly advised.

Testing the requirement against the policy

Requirements get asserted in consultation responses that do not always match the adopted policy. Check four things before accepting a figure.

Is the standard in the adopted plan, or in a supplementary document that postdates it and may carry less weight? Is the occupancy assumption the one the policy specifies, applied to the actual mix rather than an average? Has the authority applied a cost per square metre from a published schedule, and is that schedule current? And does the contribution satisfy the statutory tests, in particular the requirement that it be fairly and reasonably related in scale and kind to the development?

Where the total package of obligations makes the scheme unviable, that is demonstrated through a Viability Assessment prepared on the national guidance, and councils expect a suitably qualified author with professional review strongly advised. Open space is often the first line an authority will reduce, because it is easier to defer than affordable housing.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. To see which assessments a scheme of your size is likely to need, enter the site postcode on PlanScope.

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