Drinking water begins its journey to homes, schools and businesses from either a surface water source or a groundwater source.
Surface water sources are streams, rivers and lakes. They are on the surface of the land and are exposed to the air, rain and water flowing downhill from land near the source.
Groundwater is in the ground, not on top of it. We pull it up from wells drilled into the ground. Most groundwater comes from rain and melting snow soaking into the ground. Water fills the spaces between rocks and soils, making an “aquifer.”
About half of our nation’s drinking water comes from ground water. Most is supplied through public drinking water systems, though many families rely on their own wells. On average, eight out of 10 Pennsylvania residents receive their water from public water systems.