The San José Municipal Water System (Muni Water) serves the North San José, Alviso, Evergreen, Edenvale, and Coyote Valley communities of the City of San José. The source of your water depends on the service area in which you are located.
North San José/Alviso Service Area
Muni Water purchases a blend of Hetch Hetchy water and treated water from the San Francisco Public Utilities Commission (SFPUC) and delivers it to our Alviso and North San José customers. In 2016, the Hetch Hetchy Watershed provided most of the total SFPUC water supply, with supplementation by local watersheds in Alameda and Santa Clara counties. The major water source originates from spring snowmelt flowing down the Tuolumne River to the Hetch Hetchy Reservoir where it is stored. Since this water source meets all federal and state criteria for watershed protection, disinfection treatment practices, bacteriological quality monitoring, and high operational standards, the State and USEPA have granted this water source a filtration exemption.
The Alameda Watershed spans more than 35,000 acres in Alameda and Santa Clara counties. Surface water from rainfall and runoff is collected in the Calaveras and San Antonio reservoirs. Prior to distribution, the water from these reservoirs is treated at the Sunol Valley Water Treatment Plant (SVWTP). In 2011, the SFPUC began using ultraviolet (UV) light as an additional disinfection step for the Hetch Hetchy water supply. Fluoridation, chloramination, and corrosion control treatment are provided for the combined Hetch Hetchy and SVWTP water at the Sunol Chloramination and Fluoridation facilities.
The SFPUC actively and aggressively protects the natural water resources entrusted to its care. An annual report on the Hetch Hetchy Watershed reflects the evaluation of its sanitary conditions, water quality, and potential contamination sources. The report also presents performance results of watershed management activities implemented by the SFPUC and partner agencies to reduce or eliminate potential contamination sources. The SFPUC also conducts sanitary surveys of the local watersheds every five years. These surveys identified wildlife and human activity as potential contamination sources. The reports are available for review through the SWRCB San Francisco District office.
In 2016, groundwater from local deep water wells in North San José was utilized to supplement the SFPUC supply. With this source water change, some customers may have received a blend of groundwater and SFPUC water. A slight difference in taste and odor may be noticed since groundwater generally has a higher mineral content than surface water.
Muni Water conducted a one-time source water assessment of the wells in January of 2003.*
Evergreen Service Area
Muni Water purchases treated surface water from the Santa Clara Valley Water District (SCVWD) and delivers it to our Evergreen customers. SCVWD surface water is mainly imported from the South Bay Aqueduct, Dyer Reservoir, Lake Del Valle, and San Luis Reservoir, which all draw water from the Sacramento-San Joaquin Delta watershed. SCVWD local surface water sources include Anderson and Calero reservoirs. Water from imported and local sources is pumped to and treated at three water treatment plants located in San José.
Since 2006, the SCVWD has used ozone as the primary disinfectant. Ozone disinfection is highly effective at inactivating microbial contaminants and creates fewer disinfection by-products than chlorine. Ozone also effectively removes negative tastes and odors often caused by seasonal algal blooms in the Delta source waters.
SCVWD source waters are vulnerable to potential contamination from a variety of land use practices, such as agricultural and urban runoff, recreational activities, livestock grazing, and residential and industrial development. Imported sources are additionally vulnerable to wastewater treatment plant discharges, seawater intrusion, and wildfires in open space areas. Local sources are additionally vulnerable to contamination from commercial stables and historic mining practices. No contaminant associated with any of these activities has been detected in SCVWD treated water. The water treatment plants provide multiple barriers for physical removal and disinfection of contaminants. For additional information, visit the SCVWD website at www.valleywater.org.
Edenvale Service Area
Groundwater from deep water wells provides 100 percent of the supply for this service area. Muni Water conducted a one-time source water assessment for the Edenvale wells in January 2003.* Although the source is considered potentially vulnerable to chemical and petroleum processing activities, no contaminants associated with these activities have been detected.
Coyote Valley Service Area
Groundwater from deep water wells provides 100 percent of the supply for this service area. An assessment of these wells was conducted in June 2004,* and potable use of the groundwater began in 2005. Although the source is considered potentially vulnerable to agricultural drainage, unauthorized dumping, storage tank leaks, and sewer collection systems, no contaminants associated with these activities have been detected.
*For information about the type of contaminants tested or to get a copy of the groundwater well assessment reports for your service area, please contact a Water Quality Engineer at 408-277-3671.