A major cause of ground water contamination is effluent (outflow) from septic tanks and cesspools. Misuse of these systems for disposal of anything other than domestic or sanitary waste can pose a substantial threat to ground water and makes the system subject to Federal regulation. Residential wastewater systems can be a source of many categories of contaminants, including bacteria, viruses, nitrates from human waste, and organic compounds.
Injection wells used for domestic wastewater disposal (septic systems, cesspools, drainage wells for storm water runoff, ground water recharge wells), are of particular concern to ground water quality if located close to and up gradient of drinking water wells.
Improperly storing or disposing of household chemicals such as
paints, synthetic detergents, solvents, oils, medicines,
disinfectants, pool chemicals, pesticides, batteries, gasoline
and diesel fuel can lead to ground water contamination. When
stored in garages or basements with floor drains, spills and
flooding may introduce such contaminants into the ground water.
When thrown in the household trash, the products will eventually
be carried into the ground water because community landfills are
not equipped to handle hazardous materials. Similarly, wastes
dumped or buried in the ground can contaminate the soil and
leach into the ground water.
As urban areas grow, there is an increase in rain water runoff caused by the addition of paved surfaces. Some municipalities use storm water drainage wells to dispose of this additional runoff, particularly if the area is not served by storm sewers or has a limited sewer system. These low-cost, low-tech wells can serve as a conduit to ground water for runoff from streets, roofs, construction sites, and landscaped areas. Storm water drainage wells that communities use to control water during storm events pose a threat to ground water particularly in karst areas or areas with a high water table.
Fertilizers, herbicides, insecticides, funguicides and pesticides applied to the lawn and garden contain hazardous chemicals that can travel through the soil and contaminate ground water.
More than 11 million tons of salt are applied to roads in the Unites States annually. As ice and snow melt, or rain falls, the salt is washed into the surrounding soil. Salt also enters ground water from improperly protected storage stockpiles.
In the garage, items that are improperly used, stored, or disposed of may potentially contaminate ground water, especially if there is a drain to the ground in the floor of the garage. Sources include:
Water used in the home and entering a septic system or sewer
system may contain:
Water percolating through landfills is known as leachate. Leachate from landfills that contain household and other waste may pick up:
Lawns with overapplied or misapplied fertilizers, herbicides, insecticides and fungicides might introduce these contaminants into the ground water:
Contaminants from the road or driveway that might enter ground water include:
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