What structure protects a well from collapse and surface contamination?

The well casing is a critical structure designed to protect a well from collapse and surface contamination. It serves as a barrier to maintain the integrity of the well, preventing the surrounding soil and rock from collapsing into the wellbore. This casing is usually made of steel or plastic and extends from the surface down to the water-bearing formation. Its primary function is to isolate the well from contaminants that could enter from the surface, such as chemicals, bacteria, or other pollutants. By providing a secured environment, the well casing helps ensure the quality of the water that is extracted from the well.

Other components, like the well screen, play a role in filtering out sediment from the water entering the well, but they do not provide structural support to prevent collapse. The well pump is responsible for lifting water from the well but does not impact the structural integrity. The well vent is used to equalize pressure in the well, allowing for smooth operation of the pump, but like the pump, it does not protect against collapse or contamination of the well itself.