The most important way to have good quality groundwater is to prevent contamination. Almost all of the Earth's water is in the oceans, 97%. Freshwater is only 3%, but most of that is tied up in glaciers. Only 0.3% of the Earth's water is found in lakes, rivers, and aquifers within a half mile of the Earth's surface. Approximately 7 inches of the Alabama's 55 inches of annual rainfall enters the ground to become groundwater.
Groundwater is under your feet nearly everywhere you stand. The soil may be dry; especially in late summer, but not far below the surface the soil may be completely saturated with water. The top of the saturated zone is called the water table. Generally the water table lies a few feet to a few tens of feet underground. Freshwater in some areas of the state extends to 2,000 feet or more below the land surface. In a few areas, however; freshwater extends down to only 150 feet below the land surface. Bodies of rock, sediment or soil that can supply useful quantities of freshwater to a well are called aquifers (from Latin works meaning water and bring). A place where water comes out of the ground on a consistent basis is called a spring.
Groundwater moves an average rate of an inch per day. Groundwater is what supplies the base flow of streams. According to the Geological Survey of Alabama, seventy-four percent of the public water supply systems in Alabama rely completely or partially on groundwater. About 44% of the Alabama's population used groundwater for domestic supplies. Alabama's groundwater is generally very clean. Nitrate and bacteria are probably the most significant groundwater contaminants. Any abandoned well is a potential source of groundwater contamination. Properly sealed abandoned wells do not threaten groundwater quality.
Groundwater Regulations: Alabama Department of Environmental Management.
Water Quality Data: Geological Survey of Alabama
The information above was provided by the Geological Survey of Alabama.