Most rural areas, and some cities depend on ground water as their source for water. Driven wells consist of a series of pipes with a point at the end. The point is driven into the ground, thus the name driven, to a depth of up to 50 feet. Bored and drilled wells can be up to 100 feet and 1000 feet deep, respectively. These wells require special digging and drilling equipment.
Most rainwater is absorbed by the ground as fills the tiny spaces between soil particles.
However, excess water runs over the top of the soil until it reaches a river, stream, or reservoir. Runoff water brings pollutants it encounters along the way to the reservoir. As water seeps into the ground, it settles in the pores and cracks of underground rocks and into the spaces between grains of sand and pieces of gravel. In time, the water trickles down into a layer of rock or other material that is water tight. This water tight zone collects the ground water, creating a saturated zone known as an aquifer.