San Luis Obispo Valley

Source: CA DWR

San Luis Obispo Valley


  • Basin Name
  • San Luis Obispo Valley
  • Basin Number
  • 3-009
  • SGMA Basin Priority
  • Medium
  • Critically Overdrafted
  • No
  • Hydrologic Region Name
  • Central Coast
  • Counties
  • San Luis Obispo


Located in California’s Central Coast hydrologic region, the San Luis Obispo Valley is 12,721 acres in size. This Medium priority basin is home to an estimated 18,835 people (2010 value), which have been at a rate of 9.21.

San Luis Obispo Valley is a(n) basin with approximately 85 wells, of which approximately 48 are water supply wells. Groundwater accounts for approximately 70.33 percent of the basin’s water supply.

Source: CA DWR
Source: CA DWR

Basin Notes

2003: Bulletin 118 basin description

2014: CASGEM Basin Prioritization 2014: medium

2018: Basin prioritization: high. Comments –

  • 1) CASGEM/WDL/GWIDS: No data or data insufficent to determine GWL status. Source: DWR 2) The San Luis Obispo Valley Groundwater Basin is situated in the San Luis and Edna Valleys …Groundwater levels reported from wells within the Edna Valley have experienced fluctuations impacting the groundwater storage for the basin. USGS Well # 351258120364501 031S013E19H001M located near Pismo Creek fluctuated between 5 and 80 feet below ground surface between 1958 and 1983. Another well in Edna Valley, CDWR CASGEM 352001N1206071W001, exhibited a decline from 19- to 46-feet since 2012 due mostly to recent drought conditions. Groundwater elevations in Edna Valley has declined between 4.7 to 72.95 feet from 2005 through 2015. Source: 2015 County of San Luis Obispo Sustainable Groundwater Proposal
  • Salt intrusion: 1) The alluvium extends out to the ocean but the fresh water portion of the alluvium is upstream of the Marre weir at San Luis Bay Estates. Prior to installation of this weir in the early 1970s, seawater intrusion had occurred as far up the valley as the confluence with See Canyon Creek. Since the installation of the weir and with the supplemental flow from the City of San Luis Obispo wastewater treatment plant, there has not been any seawater intrusion documented upstream of the weir.

2018 Final Basin Prioritization: Basin status changed from medium to high priority.

GSA Information

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