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50 Ways Farmers Can Protect Their Groundwater
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37. Locate Your Well Away From Contamination Sources

wellhead

Choosing a good site for your new well may be the most important decision you make in protecting your drinking water from contamination. The decision may be difficult, however, because there are many potential sources for groundwater contamination.

Locate your wellhead on the highest ground available, well above the flood level of nearby streams. This is no guarantee that water will be safe, though, because using a well creates an area of groundwater "drawdown. " As the well pumps water from the aquifer, water beneath nearby fields moves to the well more quickly. Even contaminants in downslope areas may be drawn toward the well.

well setbacks in Illinois According to the Illinois Department of Public Health, you must locate the well at least 200 feet from potential sources and routes of contamination. However, if the owner of the private well is the same as the owner of the potential source or route of contamination, the setback is 75 feet.
Potential sources of contamination Potential sources of contamination include: landfills and disposal sites for municipal, special and hazardous waste; underground tanks containing more than 500 gallons and aboveground tanks containing more than 25,000 gallons of petroleum products; storage and handling areas for de-icers, hazardous substances, road oils, agricultural chemicals, and animal waste.
potential routes of contamination Potential routes of contamination include: abandoned and improperly plugged wells; injection wells, which are commonly used to drain surface water and dispose of industrial and municipal waste-water; and excavations related to the production of stone, sand, and gravel.
well setbacks in illinois In Illinois, wells also must be: 150 feet from existing cesspools (new cesspools are not approved in Illinois); 100 feet from leaching pits; 100 feet from a temporary manure stack (an Illinois EPA requirement); 75 feet from septic seepage tile, which should be downslope from a well; 50 feet from a barnyard, animal confinement lot, or sanitary sewer line and septic tank; and 25 feet from lakes, ponds, and streams.
dumpsite Whether you're talking about a dump site or some other contamination source, keep in mind that these lateral setback distances apply to clay- and loam-textured soils. It is recommended that they be increased for more permeable soils. For example, double these distances for highly permeable, coarse-textured soils, such as loamy sand.
diagram for well placement Ideally, place the well on the side of the contamination source opposite the flow of groundwater. If you know groundwater flows south, place the well as far north of the contaminant source as possible. In general, groundwater flows in the direction of a discharge point, such as a river, stream, or lake.
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