Because ground water moves slowly, it may be decades or even centuries before a contaminated aquifer can be used. In some cases, the contamination can never be removed and the water resource may be lost. Can Affect Your Drinking Water Most ground water used for drinking occurs near the earth's surface and is easily contaminated. Of major concern is the potential contamination of underground sources of drinking water by any of the hundreds of thousands of subsurface wastewater disposal injection wells nationwide. Waste disposal wells dispose of approximately 11 percent of the nation's fluid waste.
Injection wells can be either beneficial or a major problem.
These wells are used in a broad variety of ways from beneficial uses such as aquifer recharge and the production of oil, gas and minerals, to the improper use for disposal of toxic and hazardous wastes. The Safe Drinking Water Act of 1974 established the basic framework for protecting the drinking water of the United States. The EPA is required to regulate underground injection of fluids and fluid wastes through wells that discharge or that may discharge into or above an underground sources of drinking water . EPA has promulgated a series of Underground Injection Control Regulations to protect underground sources of drinking water. EPA defines five injection well classes EPA HQ according to the type of waste they inject and where the waste is injected.