A municipal water system is a large system of reservoirs and large-scale piping which supplies fresh water, suitable for human consumption, to houses and other residences. The network of pipes through which it is delivered are often referred to as water mains.

The pressure in the overall system is either supplied directly by a system pump or by gravity feed from a reservoir or water tower. In addition, the system usually contains a number of water purification facilities to process the water and ensure its purity before it is delivered to consumers.

These systems are usually owned and maintained by cities or other large political entities.

The advent of such 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