An introduction to the physical, chemical and biological
processes that occur in groundwater
Groundwater is an essential part of the natural water cycle.
It forms the largest available store of fresh water in the
UK. However, it is a hidden asset, out of sight and all too
often out of mind. This store of groundwater comes mostly
from rainfall that has filtered down through the ground.
Providing it is not pumped directly out of the ground, for
example for the public water supply, groundwater eventually
discharges into surface waters. Here it supports river
flows, and maintains ecosystems. It is the primary source
of water for rivers and lakes in summer or at times of drought.
Groundwater is therefore important to wildlife.
Groundwater is an important strategic resource. Three
quarters of all the groundwater pumped from boreholes or
taken from springs is used for mains water supply. It directly
supplies nearly a third of the drinking water in the UK.
Policy and regulatory information
Other country information