Much of the water used for drinking and irrigation comes from aquifers
An aquifer is an underground supply of water that occurs naturally.
Water accumulates in permeable rock or (layers of other materials like sand, gravel or silt) throughout thousands (and perhaps millions of years). Most of this water came from rains, but fissures in above-ground reservoirs (lakes and rivers) can also provide small amounts of water to the aquifer. It percolates down into the reservoir through layers of soil and rock.
Aquifers need hundreds, thousands and perhaps millions of years to fully recharge themselves. Heavy pumping from aquifers can draw the supply down faster than the aquifer can recharge itself.
At this time, heavy metals, arsenic and other harmful chemicals can leach into the aquifer.
Salt water can also penetrate aquifers, and make the water unpotable. In areas of high population density, drawdowns of aquifers can and does occur, leading to subsidence. Subsidence is the process in which the surface slowly sinks into the spaces once occupied by the water.
In places like Houston, Texas, where heavy usage has rapidly drawn down aquifers, certain areas are currently experiencing subsidence at the rate of an inch a year.
It is certainly wise to have all water tested and aquifer water is no exception. Information on water testing can be obtained by contacting your local Cooperative Extension Service.
