What is an artesian well?

An artesian well is defined by the specific characteristic of water rising to the surface due to the natural pressure within the aquifer. This occurs in a confined aquifer where the water is trapped between layers of impermeable rock or sediment. When a well is drilled into this aquifer, the internal pressure causes water to flow up the well without the need for mechanical assistance or a pump, allowing it to reach the surface spontaneously.

This phenomenon typically occurs in areas where the aquifer is recharged at a higher elevation, creating a pressure difference that forces water upward when a well is tapped. This is what distinguishes an artesian well from other types of wells, where pumps are necessary to draw water (as indicated in the first option), or from surface wells that rely on collecting rainwater (which the second option describes). The fourth option, referring to a sealed well that produces hot water, does not describe the essential feature of an artesian well focused on pressure and confined aquifers.