How it works & data sources

DPA Check gives an indicative answer to the question: does this address fall within a Designated Protected Area (DPA), where grant-funded Shared Ownership leases can carry restricted-staircasing or resale provisions?

How a result is produced

You give a location
A postcode or address (with autocomplete), coordinates as latitude/longitude or British National Grid easting/northing, or a pin dropped on the map.
We find it on the map
Postcodes resolve via postcodes.io; addresses via OpenStreetMap (or Ideal Postcodes if precise lookup is on); coordinates and pins are reverse-looked-up to the nearest postcode.
We identify the civil parish
DPAs in the 2009 Order are defined parish-by-parish, so the civil parish is the unit we match on (for a pin or coordinate, by point-in-polygon against the parish boundary).
We match it against the legislation
The parish name is checked against the schedules of SI 2009/2098. Where a name occurs in more than one county, the geocoded county/region picks the right one.
We show a verdict and a map
In a DPA, partially designated, not designated, or needs-review — with your point pinned and, where available, the parish boundary outlined from ONS data.

The four outcomes

in dpa The whole parish is designated (an “entire parish” DPA). Confident result — the entire parish is in the DPA.
partial A “by maps” parish: only part of the parish is designated (typically the rural area, excluding the built-up settlement). Your exact plot may or may not fall inside it, so the official Homes England boundary map is linked on the result — always check it.
not dpa The parish is not listed in the 2009 Order, so it is not a Designated Protected Area.
review An unparished area, or a location we couldn’t confidently classify by parish name alone. These need a manual check against the local-authority maps.

Shared Ownership in a DPA: staircasing & resale

Why does a Designated Protected Area matter? Most grant-funded Shared Ownership homes let you “staircase” to 100% ownership over time. In a DPA — typically rural areas, National Parks and Areas of Outstanding Natural Beauty — the lease can instead cap staircasing (often at around 80%, so you can’t buy the home outright) and add resale restrictions, so the home stays available and affordable for local people. This is what people are really asking when they search “why can’t I staircase to 100%?” or “can I sell my Shared Ownership property?”

Can I staircase to 100% / buy the freehold? If the property is in a DPA, possibly not — your lease may cap staircasing. Check the address here, then read your lease and ask your provider.
Are these homes harder to sell? In a DPA the provider usually has a nomination/right-to-buy-back period and the buyer must often meet local-connection criteria, so resale works differently from an open-market home.
Is the whole area affected? Not always — many parishes are designated only “by maps” (part of the parish). A green/amber result here tells you which case applies.

This explains the indication only — the precise terms are set by your individual lease and the official map. Always confirm with your Shared Ownership provider, a conveyancer and an RICS valuer.

Data sources

Source	What it provides
The Housing (Right to Enfranchise) (Designated Protected Areas) (England) Order 2009 (SI 2009/2098) — legislation.gov.uk	The legal definition of every DPA: the master list of designated parishes (“entire parish” and “by maps”). This is the authoritative basis for every verdict.
Homes England — Designated Protected Areas maps	The official boundary maps (PDFs) for “by maps” parishes, where only part of the parish is designated. Linked directly on partial-match results.
postcodes.io	Free UK postcode lookup: postcode → civil parish, local authority, region, coordinates, and the ONS parish code used to fetch the boundary.
OpenStreetMap (Photon & Nominatim)	Free address autocomplete (Photon) and free-text geocoding fallback (Nominatim), plus the base map tiles shown with each result.
Ideal Postcodes (optional)	Royal Mail PAF / AddressBase address lookup, used only when “precise address lookup” is enabled — to find exact house-level addresses and their coordinates.
ONS Open Geography Portal	Generalised civil-parish boundary polygons (Parishes & Non Civil Parished Areas, Dec 2024), used to draw the parish outline on the result map.

Contains public sector information licensed under the Open Government Licence v3.0. Map data © OpenStreetMap contributors.

Limitations

Indicative guidance only — not legal advice. Results are matched at civil-parish level against SI 2009/2098. They should not be relied on for any transaction without independent verification.

For “by maps” parishes the precise boundary is defined only by the official Homes England map — a parish-level match cannot tell you whether a specific plot is inside or outside the designated area. Always confirm against the official map.

Free address autocomplete via OpenStreetMap/Photon is street/postcode level and lacks most UK house numbers; switch on “precise address lookup” (Ideal Postcodes) for exact addresses. The parish-boundary outline is a generalised polygon for context and is not a legal boundary.

Always take professional advice before relying on a result.

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