What is the main function of an artesian well?

The primary function of an artesian well is to extract groundwater under pressure. This type of well taps into a confined aquifer—a layer of permeable rock or sediment that is saturated with water and encased by impermeable layers. The water in this aquifer is under pressure due to the weight of the water above it. When an artesian well is drilled, the pressure allows the water to rise naturally to the surface without the need for pumping.

This characteristic of artesian wells distinguishes them from other types of wells, where water must be actively pumped from the ground. The natural pressure makes artesian wells an efficient source of water supply, often yielding a steady flow of water that can be utilized for various purposes, such as irrigation, household use, or municipal water supply.

In contrast, the other options describe functions that do not match the specific mechanisms involved with artesian wells. Collecting surface water refers to processes associated with surface water sources rather than groundwater extraction. Filtering contaminants typically pertains to water treatment processes, not the specific function of a well. Monitoring water levels is a practice related to managing water resources but does not represent the action of extracting water under pressure.