Water wells are an important water source, especially in areas which experience a serious dry season and don't have other sources of water.
The ground may act as a filter, providing high quality groundwater. In other cases, the water may be polluted by industrial waste, or contaminated due to poor placement relative to a septic tank, or brackish due to saltwater incursion.
Any form of latrine or septic tank should be placed at a safe distance, to minimize contamination of the water supply. In theory this will depend on the local conditions - soil, fissures in rock, depth of the well. In practice, a distance of 10 m is often used as a safe rule of thumb.
A form of well is also used to collect rainwater - this must be surrounded by a collection area which funnels water into the well. This performs groundwater recharge, and the same well may be used to collect water.
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