When an artesian aquifer is tapped, pressure in the aquifer will force the water up the well without the use of a mechanical aid. The aquifer is surrounded by impermeable rock and typically made of sandstone or other porous rocks or sediment.

 

The pressure built up in a sloped aquifer will push water to the surface and may create a permanent fountain. Artesian water matches spring water’s range of characteristics. Vendors often promote a brand’s "artesian" quality as a distinguishing factor.