The 30 year management obligation in biodiversity net gain
Thirty years is a statutory minimum, not a management aspiration. Getting the legal mechanism, the habitat management plan and the funding right at the start avoids a dispute in year seven.
The biodiversity net gain 30 year management obligation is the part of the regime that outlives everyone who worked on the application. Planning permission is granted, the houses are built and sold, the contractor moves on, and somewhere a meadow still has to be cut twice a year and reported on until the 2050s. Getting the legal mechanism and the money right at the start is what separates a scheme that discharges its obligation cleanly from one that generates a dispute in year seven.
Three decades is not a management aspiration in the Environment Act 2021 regime. It is a minimum period written into the legislation.
Where the 30 years comes from
Schedule 14 to the Environment Act 2021 inserted Schedule 7A into the Town and Country Planning Act 1990, and that Schedule carries the machinery. A biodiversity gain condition is deemed to be attached to most planning permissions in England, and development cannot lawfully begin until the local planning authority has approved a biodiversity gain plan.
Where the plan relies on habitat created or improved on the development site, and the metric treats that work as significant, the habitat has to be maintained for at least 30 years after the development is completed. Off-site gains registered on the biodiversity gain sites register carry the same 30 year duration.
Two points are commonly misread. The clock runs from completion of the development rather than from grant of permission, which on a phased scheme means different parcels can have different end dates. And the obligation attaches to habitat that the metric scores as delivering the uplift, so retained existing habitat that was never counted is not swept in.
Securing it: condition, obligation or covenant
The legislation offers three routes for on-site work and two for off-site, and the choice has consequences.
| Mechanism | Typical use | Practical point |
|---|---|---|
| Planning condition | On-site habitat within the applicant's control | Simple, but hard to enforce against a future householder and awkward where land is later transferred |
| Section 106 planning obligation | On-site habitat, management companies, commuted sums, off-site land | Binds successors in title, registrable as a local land charge, enforceable by injunction |
| Conservation covenant | Off-site gain sites and land held for habitat | Runs with the land, made with a responsible body rather than the council |
Most authorities default to a section 106 agreement for anything of scale, because it lets them bind a management company, take a commuted sum and reserve step-in rights in one document. Conservation covenants do the same job for a habitat bank without involving the planning authority as a party, which matters when the gain site sits in a different district from the development. The mechanics of that route are set out in our note on conservation covenants under the Environment Act 2021.
A condition alone is rarely adequate for anything beyond a single parcel of open space transferred to an established management company. Councils know this, and a plan that proposes management by condition on land destined for sale will be pushed back.
What the habitat management and monitoring plan contains
The habitat management and monitoring plan, usually shortened to HMMP, is the document that makes the 30 years operable. Treat it as a maintenance manual rather than an ecological report.
It needs a baseline of habitat parcels mapped and scored using the statutory metric, with the condition assessment sheets attached. It needs a target condition for each parcel and the year by which that condition should be reached. It needs management prescriptions at a level a contractor can price: cutting dates and heights, grazing regime and stocking density, scrub control frequency, weed and invasive species treatment, tree and hedgerow maintenance, water level management where relevant.
Then it needs the monitoring schedule. Surveys are usually frontloaded in the early years when new habitat is most likely to fail, then spaced out as it establishes, and the plan should state who carries them out, what method they use, and to whom the report goes.
Finally it needs remediation triggers. This is the part most plans skip. Say what happens if a parcel is two condition grades below target at a monitoring visit: who decides, what remedial work is required, who pays, and whether the 30 year clock restarts for that parcel. Without that, a monitoring report is a document nobody has to act on.
Who holds the liability once the site is sold
Planning obligations bind the original covenantor and anyone deriving title from them, so the obligation travels with the land. That is the starting point, and then reality complicates it.
On a residential scheme the developer usually transfers the habitat land to a management company funded by estate rentcharges, or to the local authority with a commuted sum. On a commercial scheme the freeholder often keeps it. On an off-site arrangement the gain site owner keeps the land and the developer buys allocated units, in which case the developer's ongoing exposure is contractual rather than proprietary.
Whichever route is used, ask four questions before exchange. Is the party who will actually perform the management a party to the agreement? Is there a funding stream that survives the developer's exit, whether a rentcharge, a service charge or a capital sum? Can the authority step in and recover its costs if management stops? And is there a mechanism for replacing a management company that fails, without needing a deed of variation each time?
Solvency over 30 years is the hard part, because a management company with no reserve and an annual budget set in 2026 will struggle in 2041.
Costing the obligation properly
Price the whole 30 years into the appraisal at the outset, and price it as a real contract rather than a line item.
- Establishment works in years one to five, which are the most expensive and the most likely to need repeating.
- Routine management from year six onward, at a contractor rate with an inflation assumption stated.
- Monitoring visits, each with a surveyor day rate, travel and reporting time.
- Reporting and administration, including the cost of whoever compiles and submits the reports to the authority.
- A contingency for remediation, sized against the risk that a created habitat fails to reach target condition.
- The commuted sum or bond the council will ask for, plus legal fees on the agreement itself.
Where a scheme is marginal, this total matters to the viability case. It is a policy requirement rather than a discretionary contribution, so it belongs in the development appraisal as a cost before any affordable housing calculation rather than being traded against one.
Drafting problems that recur
The same handful of errors appear in agreement after agreement.
The commonest is signing the section 106 before the HMMP exists, with a clause requiring a plan to be submitted and approved later. That defers every difficult question and hands the authority a veto over the scheme's cost base after the land has been bought.
Others are more specific. Trigger points tied to occupation of the last dwelling on a scheme that is never quite finished. Monitoring obligations with no named recipient, so reports are produced and filed nowhere. Target conditions expressed as a metric score rather than as an observable habitat condition, which makes field verification impossible. No provision for events outside the landowner's control, such as flooding, disease or a statutory undertaker's works crossing the parcel. And land registry title plans that do not match the HMMP parcels, which surfaces years later when someone tries to enforce.
One more worth naming: an agreement that requires 30 years of management but contains no release mechanism at the end, leaving a covenant sitting on the title forever.
Start the ecology work early enough that the metric, the HMMP and the legal drafting proceed together. A Preliminary Ecological Appraisal commissioned in the first month of a project gives you the baseline the whole obligation hangs on, and it dictates what the Biodiversity Net Gain Assessment can claim.
Enter a postcode on PlanScope to see which reports a site is likely to need, then draft the supporting documents around the ecology programme rather than after it. The statutory biodiversity metric and the gain plan must be completed by a competent person under the Environment Act 2021 regime, and any draft PlanScope produces is a starting point for that person rather than a substitute for them. Reports are AI-assisted drafts that should be reviewed before submission, and we do not guarantee planning approval. This article is general guidance, not legal advice: take your own advice on the drafting of any planning obligation or conservation covenant.
Frequently asked questions
When does the 30 year period start?
On completion of the development rather than on grant of planning permission. That matters on a phased scheme, where different parcels reach completion at different times and therefore carry different end dates. Set out in the agreement how completion is evidenced for each parcel, because an undefined trigger causes disputes later.
Can the 30 year obligation be secured by planning condition alone?
The legislation allows it for on-site habitat, but most authorities will not accept it beyond a single parcel transferred to an established management company. A condition is hard to enforce against a future owner. A section 106 agreement binds successors in title and allows a commuted sum and step-in rights.
What has to be in a habitat management and monitoring plan?
A mapped and scored baseline using the statutory metric, a target condition and date for each parcel, management prescriptions detailed enough to be priced by a contractor, a monitoring schedule naming who surveys and who receives the report, and remediation triggers stating what happens when a parcel falls below target.
Who is liable once the developer sells the site?
A section 106 obligation binds anyone deriving title, so the duty travels with the land. In practice it is usually performed by a management company funded by rentcharges, by the local authority under a commuted sum, or by a gain site owner under a conservation covenant. Check the performing party is a named party to the agreement.
Should the 30 year cost go into the viability appraisal?
Yes, as a policy cost rather than a discretionary contribution. Include establishment works, routine management, monitoring visits, reporting, contingency for remediation, and any commuted sum or bond. Sitting it above the affordable housing calculation rather than trading against it reflects the statutory nature of the obligation.
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.