Small Water District, Large Service Area

Water Districts vary in size, services and location. While it may seem easy to compare water bills from different providers, Rainbow Water is a unique special district with a large topographical area servcing over 9,000 connections.

Location and Size

Rainbow Water is comprised of a large rural district in north San Diego County that stretches from the north at the Riverside County line near Temecula to the south at Gopher Canyon Road, and west towards Vista and Oceanside. The area covers 83 square miles with more than 9,000 water and over 3,400 sewer connections. The connectioins equates to an average of 100 accounts per square mile.  In comparison, Rancho Water is roughly 156 square miles with over 40,000 accounts or 256 per square mile. Rainbow Water and Rancho Water are two water districts located adjacent to one another with two different rate structures that are based upon their population, rate classes, and service area.

Rainbow Water has infrastructure within the 83 square mile service area that allow the safe and reliable delivery of water through a series of pipelines, tanks, valves, and pump stations. The cost to maintain those assets are similar between the two agencies, but Rancho Water has the capability to share the costs among 2.5 times as many customers as Rainbow Water. Less of a populated area equals more shared costs.

One Hundred Percent Imported Water Supply

When comparing water providers, the water supply is another factor to consider with cost of water. The water delivered to Rainbow Water’s customers is imported from hundreds of miles away. Before water reaches your tap, it travels across two thirds of the state through Metropolitan Water District of Southern California’s (Metropolitan) extensive distribution system to be treated at Metropolitan’s Robert H. Skinner Treatment Plant in Temecula. The Skinner Treatment Plant has served as a portion of Rainbow Water's water supply since 1976, and receives a blend of water from the State Water Project (SWP) and Colorado River Aqueduct. The water finally makes its way to Rainbow Water through direct connections to Metropolitan's pipelines.

Wholesale Water Provider

In October 2024, Rainbow Water completed the four year process for detachment from water wholesale provider, San Diego County Water Authority. The decision to detach was a result of numerous pass-through fixed rate charges imposed on customers that caused significant increase in water costs.

The benefits of detachment allowed for Rainbow Water to secure reliable water and hold rates steady for 2025 with purchase of water from Eastern Municipal Water District. Rainbow Water began to receive water from the Eastern Municipal Water District (EMWD) after detachment finalization from the San Diego County Water Authority (SDCWA) on November 1, 2024. The landmark change made a significant step in Rainbow Water’s commitment to securing cost-effective and reliable water supplies for its customers.