Ashley Valley Water & Sewer Improvement District is a special service district formed by Uintah County to furnish water and sewer service to the unincorporated area outside Vernal City including incorporated Naples City. It was formed in 1974 under title 17, chapter 6 Utah Code. In 1982 it began to operate and service the area outside the city, this area was formally operated by Vernal City and Naples City.

The original water system was built in 1962 by the Bureau of Reclamation as part of the Central Utah Water Steinaker Project, and the lines put in by Naples and Glines before 1962. The service area covers from 3000 north to 5800 south and 3500 west to 3500 east, an area 9 miles by 7 miles and about 8 miles of water line, 105 of distribution line and 15 miles of transmission.

The sewer system was built in 1982 as part of an EPA project. Ashley Valley Water & Sewer, Vernal City and Maeser Water Improvement District built lagoons and a joint sewer lagoon system, later replaced by an oxidation ditch treatment plant. Ashley Valley currently has 1700 sewer connections and 3500 water connections.