Ground water contamination with pesticides is frequently associated with pesticide handling practices in the vicinity of wells. Wells should be properly cased, capped and grouted. Wells that are not protected act as conduits for surface contaminants to drain into the aquifer. Open wells used near mixing-loading sites are particularly vulnerable to contamination. Grade the area around the wellhead to keep runoff away from the well.
Pesticide spills near wells can move directly and quickly nto ground water.
Avoid mixing, storing, or disposing of pesticides within 100 feet of a well. Some pesticide labels may recommend greater distances. Properly close all abandoned wells and never dispose of wastes in unused wells. Pesticide runoff and leaching are favored by rainfall soon after application. The quantity of irrigation water should be carefully controlled to minimize the potential for pesticide leaching and runoff.