Ground Water

Some of the rain that falls on Ireland filters through the soil, subsoil and rocks and becomes groundwater.  Much of that water moves slowly underground and remains there for long periods before emerging as base flow in rivers or as springs.  Some is extracted for drinking, particularly for single houses in the country, and often receives little or no treatment prior to use.

Groundwater is protected against pollution from the surface if there is sufficient depth of overlying soil and subsoil but, if that depth of cover is small, then groundwater is vulnerable from septic tank effluents and from slurry spreading.  Much of the underlying rock in Ireland is limestone that is easily dissolved by water and this has created cracks and fissures in the rock that allows pollutants from the surface to move quickly down to the underlying water body.  Hence much of Ireland’s groundwater resources are vulnerable to pollution.