Contaminated land arising from many different industrial and waste disposal practices in the past has the potential to impact on groundwater moving beneath it. In turn the groundwater can provide the pathway for movement of contaminants from beneath the land to adjacent waterways.

Microbiological Contamination can result from the inappropriate disposal of animal and human waste. A common cause of microbiological contamination of water wells is the inappropriate siting of septic tanks. Inadequate protection of the top of a borehole can also result in contaminated surface water from the surrounding area entering the borehole. To reduce this risk to the quality of water being abstracted, consideration should be given to the location of potentially polluting sources when siting a water well. It is recommended that proper sealing of the upper casing and protection of the borehole headworks is requested, and budgeted for, when planning the work with a drilling contractor.