In artesian aquifers, pressure is naturally built up due to the water being trapped between impermeable layers, often leading to the water rising above the ground surface when tapped.
Water in an artesian aquifer is typically under pressure, resulting in the water rising above the atmospheric pressure when tapped. This is because the aquifer is confined and the pressure is exerted by the overlying rocks. Hence, water rises above the atmospheric pressure when accessed, which is characteristic of artesian wells.