*Farming is an important industry in Cornwall, and this has a potential impact on the quality of private borehole water supplies. Use of pesticides can affect water quality, as can the presence of livestock.

*Cornwall Council: Private Water Supplies Webpage The geology of Cornwall also impacts on the quality of the groundwater. High levels of manganese, iron and arsenic have all been recorded in water samples taken from private borehole water supplies due to the natural presence of these within the rock.