A water supply network is a system of watersheds, or other collection systems such as drawing water from a lake or river, reservoirs and piping which delivers fresh water, suitable for human consumption, to houses and other users. The delivery systems from the reservoirs can include uncovered ground level aqueducts and underground tunnels.

Virtually all large systems are required to treat the water. This is usually done close to the final delivery points to reduce the chances for the water to become contaminated after treatment. Once treated , the water is transported by the local supply network. Frequently the "pipes" used are square concrete boxes measuring 10 feet or more in size.

Near the end point, the network of pipes, through which the water is delivered, are often referred to as water mains.

The pressure in the system is either supplied directly by a pump, or by gravity feed from a reservoir, or a water tower, or in smaller systems by a compressed air.

These systems are usually owned and maintained by cities or other large political entities (but see water privatization).

The advent of these systems (along with comparable sewage systems) was one of the great engineering advances which made urbanization possible. Improvements in the quality of the water have been one of the great advances in public health.

See also: Water, Water pipes, Water resources, Water quality, Plumbing