Groundwater is the water stored beneath the surface in the spaces between soil particles and in cracks within rocks. In the UK, groundwater is an essential resource, supplying around a third of drinking water and supporting rivers, wetlands and ecosystems. It is held in underground layers known as aquifers.

One common pollution source in the UK is agriculture

Groundwater becomes polluted when harmful substances enter the ground. One common source is agriculture. Nitrates from fertilisers and slurry can leach through soils, particularly in areas with permeable chalk or sandstone, contaminating groundwater used for drinking water.

Industrial activity is another major cause

Past and present industrial sites, such as factories can release chemicals, oils or heavy metals into the ground through leaks. Many older sites are affected by historic contamination from industries that operated before modern environmental controls were in place. Earlier this year it was revealed that RAF bases are hotspots of toxic ‘forever chemical’ pollution in water.

Urban development also contributes to pollution

Leaking sewers, poorly maintained septic tanks, and runoff from roads can introduce bacteria into the soil. In addition, landfill sites can produce contaminated liquid which may seep into underlying aquifers if not properly managed. Groundwater remediation is required when pollutants migrate through soil and contaminate underlying aquifers. Companies such as soilfix.co.uk/services/groundwater-remediation are on hand to advise.

Once polluted, groundwater is difficult to clean

This is because it moves slowly underground and contaminants can spread over wide areas. As a result, protecting groundwater is a key priority for environmental protection in the UK.