Gilroy-Hollister Valley – San Juan Bautista Area

Source: CA DWR

Gilroy-Hollister Valley – San Juan Bautista Area


  • Basin Name
  • Gilroy-Hollister Valley – San Juan Bautista Area
  • Basin Number
  • 3-003.04
  • SGMA Basin Priority
  • Medium
  • Critically Overdrafted
  • No
  • Status
  • Subject to SGMA
  • DWR Region & POC
  • South Central Regional Office
    Mike McKenzie
    (559) 230-3308

  • Number of Wells
  • 413
  • Hydrologic Region Name
  • Central Coast Hydrologic Region
  • Counties
  • San Benito


Located in California’s Central Coast hydrologic region, the Gilroy-Hollister Valley – San Juan Bautista Area is 74,325 acres in size. This Medium priority basin is home to an estimated 26,143 people (2010 value), which have been at a rate of 10.69. Gilroy-Hollister Valley – San Juan Bautista Area is a(n) basin with approximately 413 wells, of which approximately 54 are water supply wells. Groundwater accounts for approximately 93.18 percent of the basin’s water supply.

Source: CA DWR
Source: CA DWR

Basin Notes

2003: Bulletin 118 basin description

2018: Basin prioritization comment – 1) CASGEM/WDL/GWIDS: No data or data insufficent to determine GWL status. Source: DWR 2) GWLs continued to decline in areas of basin that rely on GW, specifically in the Bolsa, San Juan, Hollister West, Bolsa SE, and Tres Pinos subbasins. While some subbasins showed groundwater level increases, overall groundwater in storage decreased. Groundwater elevation declines and storage decreases during drought do not constitute overdraft; nevertheless, the continued reduced supplies of imported water in tandem with increased groundwater demands are a warning of potential overdraft. Source: San Benito County Water District

San Benito County Water District annual report

Basin boundary modification request pending that, if successful, would consolidate the Bolsa Area 3-003.02, Hollister Area 3-003.03, San Juan Bautista Area Subbasin of the Gilroy Hollister Valley and Tres Pinos Valley 3-025. This would shift supervision of the subbasin to the north central region office.

GSA Information

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