What the well records contain
GSI's wells and springs database holds drilling records reported over many decades. Depending on the record, it can include:
- Water strike depths: up to four depths where water was met while drilling. The first is the closest thing to a depth to water at that spot.
- Type: borehole, dug well or spring. Dug wells are shallow and hand- or machine-dug; boreholes are drilled, often well into rock.
- Depth of the hole and yield, where reported.
GSI says plainly that it isn't a comprehensive database: many wells were never reported. In practice, around half of nearby records have no water strike depth at all.
Reading the numbers
- A shallow strike (within about 2 m of the surface) is a flag for wet ground: foundations, basements and septic tank percolation all need care.
- Boreholes and dug wells measure different things. A dug well finds water in the subsoil; a borehole often finds it in fractures in the rock below. Don't average them together.
- Deeper isn't better. Irish bedrock carries most of its water in fractures near the surface. In GSI's records, boreholes with poor yields struck water deeper on average than those with good yields.
- Water levels change with the seasons, often by several metres. A strike recorded in summer can be shallower in winter.
What it can't tell you
- It isn't a hydrogeological site investigation. A trial hole, or a well drilled on the site, is what actually tells you.
- An absence of records says nothing about whether there's water. It only means nobody reported a well.
Related
- Groundwater vulnerability: how protected the groundwater is
- Aquifers: how much water the ground is likely to yield
Sources
- Geological Survey Ireland: Groundwater Wells and Springs database, gsi.ie
Last reviewed 2026-10-02.