Water Well Basics

A well gets its water from an underground source called groundwater. Ground water is a resource found under the earth’s surface. Most ground water comes from rain and melting snow soaking into the ground. Water fills the spaces between rocks and soils, making an “aquifer”. Ground water, its depth from the surface, quality for drinking water, and chance of being polluted, varies from area to area. Generally, the deeper the well, the better the ground water. The amount of new water flowing into the area also affects ground water quality.

Dug wells

Hacking at the ground with a pick and shovel is one way to dig a well. If the ground is soft and the water table is shallow,then dug wells can work. They are often lined with stones to prevent them from collapsing. They cannot be dug much deeper than the water table -- just as you cannot dig a hole very deep when you are at the beach... it keeps filling up with water!

Driven wells

Driven wells are still common today. They are built by driving a small-diameter pipe into soft earth, such as sand or gravel. A screen is usually attached to the bottom of the pipe to filter out sand and other particles. Problems? They can only tap shallow water, and because the source of the water is so close to the surface, contamination from surface pollutants can occur.

Drilled wells

Most modern wells are drilled, which requires a fairly complicated and expensive drill rig. Drill rigs are often mounted on big trucks. They use rotary drill bits that chew away at the rock, percussion bits that smash the rock, or, if the ground is soft,large auger bits. Drilled wells can be drilled more than 1,000 feet deep. Often a pump is placed at the bottom to push water up to the surface.