San Luis Obispo County Water Resources

Public Works Department


Los Osos Valley Groundwater Basin Non-Adjudicated "Fringe Areas"


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The Los Osos Valley Groundwater Basin, DWR Bulletin 118 Basin No. 3-08, is bounded on the north by Park Ridge, on the south by Irish Hills, on the west by Morro Bay, and on the east by a drainage divide separating Los Osos Valley from San Luis Valley. The Los Osos Basin, as defined by DWR, is located in San Luis Obispo County and covers 6,990 acres (10.9 square miles).


In 2015, the State legislature approved a new groundwater management law known as the Sustainable Groundwater Management Act (SGMA). SGMA requires that high and medium priority basins comply with the new law, with certain exceptions for listed adjudicated basins. DWR categorized the Los Osos Valley Groundwater Basin as a high priority basin and designated the basin to be in a “condition of critical overdraft”. SGMA does not apply to the portion of the Los Osos basin that is at issue in the litigation (“adjudicated area”) provided that certain requirements are met by the Los Osos Basin Management Committee. However, there are “fringe areas” outside of the adjudicated area, but within the State-determined basin boundaries that must comply with the new groundwater management requirements. These “fringe areas” are referred to as the Eastern Valley Area and the Southern Beach Area. The maps below show both the adjudicated areas exempt from SGMA, and the fringe areas that are subject to SGMA.



Interactive Map of Los Osos Basin

Welcome to the SGMA Interactive Data Viewer for the Los Osos Basin! This is an interactive mapping system to help you to navigate around the Los Osos Basin by panning, zooming, or searching for a specific parcel or street address. There are different map layers that can be shown and superimposed in this interactive mapping system such as boundaries of groundwater basins, cities, roads, SGMA eligible entities, and others by checking the layer names indicated on the left panel layer menu. To search and locate a specific APN or street address on the map:


1. Enter either the nine-digit parcel number (APN) including hyphens or the complete street address in the “Search...” bar on the upper right hand corner of the map screen and then click on the search button to locate it. The APN or street address that you just entered will appear on the left panel and a location marker will show up on the map to identify the location.

2. Click on the APN or street address name shown on the left panel layer menu will zoom in to the specified location for a close-up look


Click here to open the Interactive Map of Los Osos Groundwater Basin in a new window




Current News, Information, and Upcoming Meetings

Upcoming Meeting:


    Los Osos Basin "Fringe Areas" - Stakeholder Forum

    Wednesday, July 26, 2017

    6:30 PM - 8:00 PM

    CAL FIRE / SLO County Fire - South Bay Training Center

    Multi-Purpose Room

    880 Manzanita Drive

    Los Osos, CA 93402



More Information

For more information on the Sustainable Groundwater Management Act, please visit the County SGMA website.



How to Get Involved?

  • Check back to see current news, information, and upcoming meetings.
  • Attend upcoming meetings.
  • Sign up for the SGMA Mailing List here.
  • Contact Information:
    • County - Cathy Martin

      (805) 781-5275


SGMA Mailing List

Please select from the following list(s):


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