Gilroy-Hollister Valley – Llagas Area

Source: CA DWR

Gilroy-Hollister Valley – Llagas Area


  • Basin Name
  • Gilroy-Hollister Valley – Llagas Area
  • Basin Number
  • 3-003.01
  • SGMA Basin Priority
  • High
  • Critically Overdrafted
  • No
  • Status
  • Subject to SGMA
  • DWR Region & POC
  • North Central Regional Office
    Bill Brewster
    (916) 376 9657

  • Number of Wells
  • 2196
  • Hydrologic Region Name
  • Central Coast Hydrologic Region
  • Counties
  • Santa Clara


Located in California’s Central Coast hydrologic region, the Gilroy-Hollister Valley – Llagas Area is 47,371 acres in size. This High priority basin is home to an estimated 88,905 people (2010 value), which have been at a rate of 11.35. Gilroy-Hollister Valley – Llagas Area is a(n) basin with approximately 2196 wells, of which approximately 96 are water supply wells. Groundwater accounts for approximately 40.22 percent of the basin’s water supply.

Source: CA DWR
Source: CA DWR

Basin Notes

2003: Bulletin 118 basin description

2016: Basin boundary modification approved

Revised basin boundary description

2018: Basin prioritization groundwater level comment – [Santa Clara Valley Water District ]Annual Report shows stable longterm hydrographs for the most part. Source:

2018 Final Basin Prioritization: Basin status remains unchanged at high priority.

GSA Information

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