Groundwater Info Center
History of Bulletin 118

Click on a year for more on key legislation and events related to Bulletin 118.

  1. Water Quality Investigations Report No. 3:
    Ground Water Basins in California (1952)


    The Bulletin 118 series was preceded by Water Quality Investigations Report No. 3: Ground Water Basins in California, published in 1952 by the Department of Public Works and Division of Water Resources (the predecessor of DWR). This report identifies 223 alluvium-filled valleys believed to contain usable groundwater. Click here to view the report.


  2. Bulletin 118-75: California's Ground Water


    Bulletin 118-75: California's Ground Water summarized available information from DWR, U.S. Geological Survey, and other agencies for individual groundwater basins to "help those who must make decisions affecting the protection, additional use, and management of the State's ground water resources." Bulletin 118-75 contains a summary of technical information for 248 of the 461 identified groundwater basins, subbasins, and what were referred to as "areas of potential ground water storage" in California as well as maps showing their location and extent. The Bulletin 118-75 basin boundaries were based on geologic and hydrogeologic conditions except where basins were defined by a court decision. Click here to view the report.

  3. California Water Code Section 12924


    In 1978, Section 12924 was added to the California Water Code, establishing DWR's ongoing responsibility to investigate the state's groundwater basins:


    "The Department shall, in conjunction with other public agencies, conduct an investigation of the State's groundwater basins. The Department shall identify the State's groundwater basins on the basis of geologic and hydrogeologic conditions and consideration of political boundary lines whenever practical. The Department shall also investigate existing general patterns of groundwater pumping and groundwater recharge within such basins to the extent necessary to identify basins which are subject to critical conditions of overdraft."

  4. Bulletin 118-80: Ground Water Basins in California: A Report to the Legislature in Response to Water Code Section 12924


    Ground Water Basins in California: A Report to the Legislature in Response to Water Code Section 12924 updated boundaries on 36 groundwater basins. The changed boundaries combined several basins based on geologic or political considerations and divided the San Joaquin Valley groundwater basin into many smaller subbasins based primarily on political boundaries. These changes resulted in the identification of 447 groundwater basins, subbasins, and areas of potential groundwater storage. Bulletin 118-80 identified 11 basins as subject to critical conditions of overdraft. Click here to view the report.

  5. Budget Act of 1999


    Despite California's heavy reliance on groundwater, basic information for many of the groundwater basins is lacking. Particular essential data necessary to provide for both the protection and optimal use of this resource is not available. To this end, the California Legislature mandated in the Budget Act of 1999 that DWR prepare:


    "...the statewide update of the inventory of groundwater basins contained in Bulletin 118-80, which includes, but is not limited to, the following: the review and summary of boundaries and hydrographic features, hydrogeologic units, yield data, water budgets, well production characteristics, and water quality and active monitoring data; development of a water budget for each groundwater basin; development of a format and procedures for publication of water budgets on the Internet; development of the model groundwater management ordinance; and development of guidelines for evaluating local groundwater management plans."

  6. Bulletin 118-03: California's Groundwater - Update 2003


    Bulletin 118 - Update 2003: California's Groundwater is the most recent comprehensive report on groundwater since 1980 when Bulletin 118-80 was published. Bulletin 118 is currently being updated in three phases as described here.


    Bulletin 118-03 includes guidance and tools that will assist local agencies in effectively managing groundwater as a sustainable part of their water supplies. Bulletin 118-03 includes a description of current groundwater management efforts by local water agencies, required and recommended components of effective groundwater management plans, and a model ordinance that can be used by local governments. In addition, Bulletin 118-03 describes the roles of state and federal agencies in protecting groundwater quantity and quality. Click here to view the report.


    Online technical descriptions and GIS compatible maps of 515 groundwater basins and subbasins were part of the effort to publish the bulletin. The basin and subbasin descriptions include information about the geology, groundwater quantity and quality, and current groundwater management practices in the basins. The Bulletin 118-03 basin maps and descriptions are now viewable in the Basin Boundary Assessment Tool (BBAT).

  7. Water Code Update (Section 12924)


    TIn 2009, California Statewide Groundwater Elevation Monitoring legislation (SBx7-6) was passed, modifying Section 12924 of the Water Code to require DWR to "report its findings [on the investigation of the State's groundwater basins described in paragraph (a)] to the Governore and the Legislature not later than January 1, 2012, and thereafter in years ending in 5 or 0."

  8. Sustainable Groundwater Management Act (2014)


    The Sustainable Groundwater Management Act (SGMA), passed by the Legislature and signed by the Governor in September 2014, established a path for achieving sustainable groundwater management through the formation of GSAs and the adoption and implementation of GSPs or alternative plans.


    SGMA added various provisions to the Water Code that directly or indirectly relate to Bulletin 118, including (emphasis added):


    10720.7 (a) (1)"By January 31, 2020, all basins designated as high- or medium-priority basins by the department that have been designated in Bulletin 118, as it may be updated or revised on or before January 1, 2017, as basins that are subject to critical conditions of overdraft shall be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans pursuant to this part."

    10721 (b)"Basin" means a groundwater basin or subbasin identified and defined in Bulletin 118 or as modified pursuant to Chapter 3 (commencing with Section 10722)."

    10721 (c)"Bulletin 118" means the department's report entitled "California's Groundwater: Bulletin 118"; updated in 2003, as it may be subsequently updated or revised in accordance with Section 12924."

    10722"Unless other basin boundaries are established pursuant to this chapter, a basin's boundaries shall be as identified in Bulletin 118."

    10722.2 (a)"A local agency or an entity directed by the court in an adjudication action to file the request may request that the department revise the boundaries of a basin, including the establishment of new subbasins …"

    10722.4 (a)"Pursuant to Section 10933, for the purposes of this part the department shall categorize each basin as one of the following priorities:
    (1) High priority.
    (2) Medium priority.
    (3) Low priority.
    (4) Very low priority.
    (b) The initial priority for each basin shall be established by the department pursuant to Section 10933 no later than January 31, 2015.

    (c) Any time the department updates Bulletin 118 boundaries pursuant to subdivision (b) of Section 12924, the department shall reassess the prioritization pursuant to Section 10933."

  9. 2016 Bulletin 118 Interim Update


    DWR released the 2016 Bulletin 118 Interim Update in December, 2016. The 2016 Bulletin 118 Interim Update provides Groundwater Sustainability Agencies (GSAs) with three critical pieces of information to develop and implement groundwater sustainability plans (GSPs) or alternatives to GSPs (Alternatives): Critical Conditions of Overdraft, Basin Boundaries, and Basin Priority, The basin prioritization results will be released as an addendum to the Interim Update in fall, 2017.