Where your water comes from

Where your water comes from

Around 85 per cent of the water we supply to our customers comes from underground, from the deep water-holding rocks (called aquifers) in the chalk of the North Downs or the large deposits of greensand south of the Downs. When it rains, water runs into streams and rivers and soaks into the ground. In spring and summer much of it evaporates or is used by plants and trees but in winter the rain seeps into the topsoil and into the rock beneath the surface. Our boreholes are sunk into these aquifers and the groundwater is pumped to the surface and to the nearest treatment works.

The rest of our water comes from our reservoir at Bough Beech, near Edenbridge, which is filled from the River Eden in Kent. The reservoir is two kilometres long, 23 metres deep and holds ten billion litres of water. We can only fill the reservoir during the autumn and winter months when the river is flowing at the required level.

Groundwater is high quality as it has been naturally filtered as it percolates through the rocks. However, it contains dissolved minerals from the rocks meaning it is classed as hard water which we then soften.

River water is treated in a different way as it requires more filtration to ensure it is safe to drink. Chemicals such as fertilisers and pesticides also need removing.

You can find out how we look ahead 60 years to understand how much water will be available and how much we will need to supply by reading our Water Resources Management Plan.