Starting in the late 1800's, water for McKinleyville came from private wells. By 1960, it was clear that McKinleyville's groundwater supply was not adequate for community needs. Additionally, serious concerns were raised regarding the quality of well water. The District's first challenge was to develop a safe and reliable source of supply to replace the private wells. After studying all alternatives, the Board applied for a state grant and low interest loan to fund the construction of a system-wide distribution system. MCSD competed successfully and secured the needed funding so that the system could be built. MCSD started serving water in 1972. At that point 1,780 customers joined in.
Today, the District has about 6,700 active water customers with a projected growth rate of four percent per year. The District purchases its wholesale supply from the Humboldt Bay Municipal Water District. Water is diverted at HBMWD's million-gallon tank on Essex Hill and is piped under the Mad River to MCSD's Grant A. Ramey Pump Station at the intersection of North Bank Road and Azalea Avenue. Water is then pumped into the primary pressure zone, which serves all of the District except McCluski Hill. The District has two reservoir sites (Cochran Road and Norton Road) in the primary pressure zone with 2.5 million gallons of storage at both sites.
Customers on McCluski Hill, in the high-pressure zone, access the 250,000 gallons of storage at the hilltop tank site. Water is pumped from the Cochran Tank site to fill the hilltop tanks. The District owns and maintains approximately 84 miles of mains.