Could a sinkhole open up here?
Could a sinkhole open here — and has the ground already moved?
Every sinkhole story ends with “there was no warning”. Usually there was, in three places nobody reads together: the British Geological Survey’s rating of whether the rock under the area dissolves, the register of mine entries beside it, and the satellite record of whether the ground has already been measured moving. Enter a postcode or a spot and we read all three, free. Honest limits first: the soluble-rock rating is a 5 km grid, so it describes the area rather than the house, the mine-entry layer is presence within 100 m, and nobody can predict a sinkhole — this reports the setting, the record and the movement, which is what a specialist would start from.
What the check reads
Soluble rock
the BGS GeoSure rating for dissolution — chalk, limestone, gypsum or salt — in the 5 km area, and the nearest rated area when the point sits just outside one
Mine entries
whether a recorded shaft or adit lies within about 100 m: the crown-hole mechanism that opens most of Britain’s "sinkholes"
Measured ground motion
the European Ground Motion Service reading at the nearest measured cell — is this ground already sinking, and how fast
One verdict, with its reasons
Low, Moderate or Significant, each stated with the evidence behind it and the limits of that evidence
The check is free and stays free. For a purchase, the £19 HomeGround report maps the mine entries and coalfield risk areas in full, with the radon, flood and ground-hazard picture beside them.
What actually causes sinkholes in Britain?
Two things, and they live in different databases. The first is dissolution: rainwater and groundwater slowly eat chalk, limestone, gypsum and salt, leaving cavities that the ground above eventually falls into. Gypsum is the fastest — it dissolves about a hundred times quicker than limestone, which is why Ripon in North Yorkshire produces a new hole every few years — and the Cheshire salt field, the Mendip and Peak District limestone, and the chalk of the Chilterns and Downs all have their own histories. The second is collapse over old workings: a filled or forgotten mine shaft, or a shallow gallery, gives way and a "crown hole" opens, sometimes a century after the pit closed. Britain has more than 175,000 recorded mine entries. On top of both sit the man-made triggers — a burst water main washing fine soil into a void, an old culvert or soakaway, poorly compacted made ground — which are not mapped anywhere and can open a hole on any geology.
Can you predict a sinkhole?
No, and neither can anyone else — we would rather say that plainly than sell you a number. What can be known is the setting (does the rock under this area dissolve, is there a recorded mine entry next door), the record (has the ground here been measured moving), and the triggers (heavy rain after drought, a leaking main, new loading). This check reads the first two from public data. The British Geological Survey rates soluble-rock potential on a 5 km grid, so it describes the area, not your house; the mine-entry layer says whether an entry is recorded within about 100 m, not exactly where; and the ground-motion measurement is a satellite reading at the nearest measured cell, not a survey of your walls. Treat a Significant result as a reason to ask questions, not a verdict on the building.
Was the Nicolas Cage driveway collapse a sinkhole?
Not in the geological sense, and the distinction matters for what you check. The Malibu collapse that made headlines in September 2026 was reported by the Associated Press as coastal erosion after the remnants of Tropical Storm Marie, with a gas leak in the mix — a cliff-edge failure, not the dissolution of soluble rock. Most "sinkhole" headlines are like this: burst mains, washed-out fill, collapsed culverts, cliff retreat. A true dissolution sinkhole needs soluble rock, and a crown hole needs old workings. That is why this check starts by asking which of those is actually under the point, rather than treating every hole in the news as the same phenomenon.
My result says Significant. What should I do?
First, read what it is rating: the 5 km area around the point has rock that can dissolve, or a recorded mine entry sits within 100 m. That is a common setting — roughly one part in eight of Great Britain carries a Moderate or Significant soluble-rock rating — and the overwhelming majority of homes on it never see a hole. What changes is the questions worth asking. For a purchase: a ground-stability report from a specialist (the full HomeGround report reads the mine-entry and coalfield picture in detail), the seller’s answers on subsidence and underpinning, and whether the insurer asks about ground conditions. For a home you already own: watch for the signs that precede a collapse — a new depression in a lawn or drive, cracks that open and close with the seasons, a door that has started to stick, water that drains somewhere it did not before — and if the measured ground motion on your result is already negative, take those signs more seriously, faster.
Does a Low result mean my house is safe?
It means the two mapped mechanisms are not indicated here: the area is not rated for soluble rock and no recorded mine entry lies within 100 m. It cannot rule out an unrecorded shaft — the register is incomplete before the 1870s — or a burst main, an old culvert or badly compacted fill, none of which any map holds. Absence of a rating on a 5 km grid is also not a measurement of your ground; where the satellite record shows the point stable, that is the stronger evidence, and the result shows it.
Which areas are covered?
The soluble-rock rating comes from the BGS GeoSure national dataset, which covers Great Britain — England, Scotland and Wales — and not Northern Ireland, where the Geological Survey of Northern Ireland holds the equivalent. Mine entries come from the Mining Remediation Authority’s open coal layers, so they cover coal mining rather than tin, lead, chalk or stone workings. The ground-motion layer is the European Ground Motion Service, which measures most built-up ground in Britain but not every field; where no cell lies within 300 m, the result says so rather than guessing.
Sources: BGS GeoSure soluble rocks, 5 km summary grid (Open Government Licence) — contains British Geological Survey materials © UKRI; Mining Remediation Authority mine-entry layer (OGL); European Ground Motion Service (Copernicus). A screening from public data at area scale, not a ground investigation and not a prediction: it says what setting the point is in and whether the ground has been measured moving, and no more. For any purchase or structural decision, commission a specialist.
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