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AB-1466 • 2026

Groundwater adjudication.

Groundwater adjudication.

Children Water
Enacted

This bill passed the Legislature and reached final enactment based on the latest official action.

Sponsor
Hart
Last action
2025-10-11
Official status
Chaptered by Secretary of State - Chapter 643, Statutes of 2025.
Effective date
Not listed

Plain English Breakdown

Checked against official source text during the last sync.

Groundwater Adjudication Rules

This law changes how courts handle small water users and requires more detailed information from parties involved in groundwater disputes.

What This Bill Does

  • Allows the court to treat people who use very little groundwater separately instead of exempting them from proceedings.
  • Requires a hearing within a set time frame to decide if these small users should be treated separately or not.
  • If someone uses less than 100 acre-feet of water per year, their claims are presumed accurate unless challenged by another party.
  • For agricultural use, requires detailed information about crops and irrigated land over the past ten years in initial disclosures.
  • Requires groundwater sustainability agencies to provide technical reports on unreported groundwater usage when requested by the court.

Who It Names or Affects

  • People who extract or divert small amounts of groundwater
  • Courts handling groundwater disputes
  • Groundwater sustainability agencies

Terms To Know

acre-foot
A unit used to measure water, equal to the amount needed to cover an acre of land one foot deep.
groundwater sustainability agency
An organization responsible for managing and planning sustainable use of groundwater in a specific area.

Limits and Unknowns

  • The bill does not specify the exact time frame for hearings or how costs related to technical reports will be paid.
  • It is unclear what happens if a party challenges the accuracy of initial disclosures that are presumed accurate under this law.

Bill History

  1. 2025-10-11 California Legislative Information

    Chaptered by Secretary of State - Chapter 643, Statutes of 2025.

  2. 2025-10-11 California Legislative Information

    Approved by the Governor.

  3. 2025-09-23 California Legislative Information

    Enrolled and presented to the Governor at 4 p.m.

  4. 2025-09-11 California Legislative Information

    Senate amendments concurred in. To Engrossing and Enrolling. (Ayes 69. Noes 1. Page 3331.).

  5. 2025-09-10 California Legislative Information

    In Assembly. Concurrence in Senate amendments pending.

  6. 2025-09-10 California Legislative Information

    Read third time. Passed. Ordered to the Assembly. (Ayes 35. Noes 5. Page 2823.).

  7. 2025-09-08 California Legislative Information

    Read second time. Ordered to third reading.

  8. 2025-09-04 California Legislative Information

    Read third time and amended. Ordered to second reading.

  9. 2025-08-26 California Legislative Information

    Read second time. Ordered to third reading.

  10. 2025-08-25 California Legislative Information

    From committee: Be ordered to second reading pursuant to Senate Rule 28.8.

  11. 2025-08-13 California Legislative Information

    In committee: Hearing postponed by committee.

  12. 2025-07-17 California Legislative Information

    Read second time and amended. Re-referred to Com. on APPR.

  13. 2025-07-16 California Legislative Information

    From committee: Amend, and do pass as amended and re-refer to Com. on APPR. (Ayes 11. Noes 2.) (July 15).

  14. 2025-07-09 California Legislative Information

    From committee: Do pass and re-refer to Com. on JUD. (Ayes 5. Noes 2.) (July 8). Re-referred to Com. on JUD.

  15. 2025-06-26 California Legislative Information

    From committee chair, with author's amendments: Amend, and re-refer to committee. Read second time, amended, and re-referred to Com. on N.R. & W.

  16. 2025-06-18 California Legislative Information

    Referred to Coms. on N.R. & W. and JUD.

  17. 2025-06-05 California Legislative Information

    In Senate. Read first time. To Com. on RLS. for assignment.

  18. 2025-06-04 California Legislative Information

    Read third time. Passed. Ordered to the Senate. (Ayes 50. Noes 20. Page 2074.)

  19. 2025-05-08 California Legislative Information

    Read second time. Ordered to third reading.

  20. 2025-05-07 California Legislative Information

    From committee: Do pass. (Ayes 11. Noes 4.) (May 7).

  21. 2025-04-22 California Legislative Information

    From committee: Do pass and re-refer to Com. on APPR. (Ayes 9. Noes 3.) (April 22). Re-referred to Com. on APPR.

  22. 2025-04-09 California Legislative Information

    From committee: Do pass and re-refer to Com. on JUD. (Ayes 9. Noes 4.) (April 8). Re-referred to Com. on JUD.

  23. 2025-04-02 California Legislative Information

    Re-referred to Com. on W. P., & W.

  24. 2025-04-01 California Legislative Information

    From committee chair, with author's amendments: Amend, and re-refer to Com. on W. P., & W. Read second time and amended.

  25. 2025-03-17 California Legislative Information

    Referred to Coms. on W. P., & W. and JUD.

  26. 2025-02-24 California Legislative Information

    Read first time.

  27. 2025-02-22 California Legislative Information

    From printer. May be heard in committee March 24.

  28. 2025-02-21 California Legislative Information

    Introduced. To print.

Official Summary Text

AB 1466, Hart.
Groundwater adjudication.
(1) Existing law establishes procedures for the comprehensive adjudication of groundwater rights in civil court. Under existing law, if the court finds that claims of right to extract or divert only minor quantities of water, as defined, would not have a material effect on the groundwater rights of other parties, the court may exempt those claimants from the proceedings, except as specified. Existing law further prescribes that a judgment in a comprehensive adjudication to determine rights to extract groundwater in a basin is not binding on, among others, claimants whose claims have been exempted.
This bill would authorize a court, in lieu of the exemption process described above, to treat persons with claims of right to extract or divert only minor quantities of water separately from other parties to the comprehensive
adjudication. The bill would require the court to hold a hearing within a specified time to determine whether to exempt or treat those claimants separately and to establish a procedure to register and administer such claims.
(2) Existing law, in a comprehensive adjudication of groundwater rights in civil court, requires a party to serve on the other parties and the special master, if appointed, an initial disclosure that includes certain information within six months of the party’s appearance in a comprehensive adjudication, except as specified. Existing law requires that information to include a description of the general purpose for which the groundwater has been used and the area in which the groundwater has been used.
This bill would require the court to presume the accuracy of the facts asserted by a party in the initial disclosure described above if the party claims an annual extraction of not
more than 100 acre-feet of water. The bill would provide that a party who challenges the facts asserted in an initial disclosure that qualifies for this presumption has the burden of proving the inaccuracy of those facts. The bill would, if the groundwater has been used for an agricultural use, require the initial disclosure to include information regarding the type of crops grown and the number of acres irrigated during the preceding 10 years.
(3) Existing law, the Sustainable Groundwater Management Act, requires all groundwater basins designated as high- or medium-priority basins by the Department of Water Resources to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans, except as specified. Existing law authorizes any local agency or combination of local agencies overlying a groundwater basin to decide to become a groundwater sustainability agency for that basin and imposes specified duties upon
that agency or combination of agencies, as provided.
This bill would require the court to, in any adjudication in a basin where one or more groundwater sustainability agencies have adopted a groundwater sustainability plan that has been approved by the department, request that the groundwater sustainability agency provide a technical report, to the extent that the agency is able to do so at a reasonable effort and expense. The bill would require such a report to, at a minimum, quantify and describe the groundwater use of parties that have not otherwise appeared before the court, as provided. The bill would provide for the payment or reimbursement of costs related to the technical report, as provided. The bill would permit the court during the pendency of the report to award interim or partial payments to be made by the parties, upon a motion with proper notice, as specified, by a groundwater sustainability agency, and following a hearing. The bill would provide that
the technical report shall be prima facie evidence of the physical facts found in the report, as provided.

Current Bill Text

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