Groundwater Pollution Risk
Most of the time, water from boreholes or wells will be quite safe to drink. However, you should be aware of the following if you intend to drink untreated water from a well or borehole.
Groundwater quality problems can arise due to natural conditions in the ground or through pollution from human activity.
Quality problems can be caused by iron, manganese, hydrogen sulphide and hardness.
Iron and manganese are commonly found in gravels and rocks, principally in an insoluble form. Dissolved iron and manganese in well water oxidize when in contact with air, forming tiny rust particles that cause discolouration of the water.
The concentration of sulphate in water is readily reduced to sulphide causing a pungent odour when aerated at the surface. Hardness is a natural characteristic of groundwater causing scaling and blockages in pipes, when levels exceed 200mg/ltr.
Human activity has not yet caused the same degree of pollution problems to groundwater in the UK as in some other E.C. countries. However, an increasing number of localised problems are coming to the attention of groundwater researchers, where wells are polluted by point sources such as septic tank systems and farmyards.
This can result in localised pockets of pollution. This will have an impact on any development requiring water in the vicinity. So, although the actual quantity of polluted groundwater is small in most areas, it can result in significant health risks.
General tips for People who use private water wells or water boreholes
- Make a note of the age and depth of your well, or in the case of a borehole, the length of its casing (the pipe inside the drilled hole).
- Learn about the types of soil, bedrock and water supply problems in your area.
- Should you be about to commission a borehole or, have just had one installed, please refer also to our Testing Schedule page.
- Find out when your drinking water was last tested. Know what tests were run, and the results. Keep records of any tests or repairs that you make.
- Contact the Health or Environment Officer at your local council. Many local or district councils will test your well or borehole water for basic contaminants and bacteria free of charge!
- Test for bacteria.
- Test for nitrate. This is especially important if there is a pregnant woman or infant in your home. Nitrates come from fertilizer use, farmyard runoff, and septic systems. A high nitrate level may mean that your water also has bacteria or farm chemicals.
You may want to do other tests. If your well is near an old landfill, oil/petrol storage, or buried fuel tank you might want to test for volatile organic chemicals (VOCs). If your well is near an orchard or farm field, a test for pesticides might be advised.
Have your water tested if you notice a change in its taste, odour, or colour. Some tests are expensive and may be hard to do. Contact us, or your local council health department for help.
- If your water contains bacteria or chemicals, find the source of the problem. Fix it and test the water again to be sure it is safe.
- Keep chemicals, septic tanks, and animal waste as far away as you can from your well. Dispose of chemicals, batteries, electrical components and motor oil properly. Don't put waste chemicals in your septic system. Limit your use of lawn and garden chemicals.
- Keep the area around your well clean.
- If your well is near an orchard or farm field, a test for pesticides might be advised.
- Have your water tested if you notice a change in its taste, odour, or colour.