<P> Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location , and deep or confined wells , sunk through an impermeable stratum into an aquifer beneath . A collector well can be constructed adjacent to a freshwater lake or stream with water percolating through the intervening material . The site of a well can be selected by a hydrogeologist , or groundwater surveyor . Water may be pumped or hand drawn . Impurities from the surface can easily reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided . Well water typically contains more minerals in solution than surface water and may require treatment before being potable . Soil salination can occur as the water table falls and the surrounding soil begins to dry out . Another environmental problem is the potential for methane to seep into the water . </P>
<P> Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location , and deep or confined wells , sunk through an impermeable stratum into an aquifer beneath . A collector well can be constructed adjacent to a freshwater lake or stream with water percolating through the intervening material . The site of a well can be selected by a hydrogeologist , or groundwater surveyor . Water may be pumped or hand drawn . Impurities from the surface can easily reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided . Well water typically contains more minerals in solution than surface water and may require treatment before being potable . Soil salination can occur as the water table falls and the surrounding soil begins to dry out . Another environmental problem is the potential for methane to seep into the water . </P>
what is the typical source of well water
what is the typical source of well water
aquifer
aquifer