Title 10. Actions In Particular Cases · Chapter 7. Actions Relating to Groundwater Rights · Article 12. Special Master · Last amended 2026 · Last verified July 28, 2026
In one sentenceSection 845 lets the court appoint one or more special masters to investigate issues, conduct factfinding, and develop preliminary injunction proposals, with compensation the court allocates equitably among the parties, and lets the court request a groundwater sustainability agency's technical report on unrepresented parties' water use.
(a)The court may appoint one or more special masters whose duties may include the following:
(1)Investigating technical and legal issues, as directed by the court. The special master shall compile a report of findings in accordance with Section 846.
(2)Conducting joint factfinding with the parties, their designees, or both.
(3)Investigating the need for, and developing a proposal for, a preliminary injunction pursuant to Article 13 (commencing with Section 847).
(4)Performing other tasks the court may deem appropriate.
(b)The court shall fix the special master's compensation on the basis and terms stated in the appointing order, and the court may set a new basis and new terms after giving the parties notice and an opportunity to be heard. The court shall allocate payment of the special master's compensation among the parties in an amount and a manner that the court deems equitable. The court may waive a party's obligations to pay the special master's compensation upon a showing of good cause.
(c)The court may request the State Water Resources Control Board or the department to recommend candidates for appointment as a special master or to review the qualifications of candidates.
(1)In any adjudication in a basin in which one or more groundwater sustainability agencies have adopted a groundwater sustainability plan that has been approved by the Department of Water Resources, the court shall request that the groundwater sustainability agency provide a technical report, if the agency is able to do so at a reasonable effort and expense. The report shall, at a minimum, quantify and describe the groundwater use of parties that have not otherwise appeared before the court. The groundwater sustainability agency may include in the report, but is not limited to, parties excused or treated separately pursuant to subdivision (d) of Section 833, parties for which the court lacks jurisdiction, and parties that have been, or it is anticipated may be, found in default by the court. The groundwater sustainability agency may provide the report at its own election, and may include areas outside of its jurisdictional boundary if another groundwater sustainability agency in the basin is unable or unwilling to provide a report.
(2)A groundwater sustainability agency that provides a report pursuant to paragraph (1) shall not be entitled to a fee for its services, but shall be paid or reimbursed the total expense incurred by the agency, including salaries, wages, traveling expenses, and all costs of whatsoever character are properly chargeable to providing the report. The court shall apportion the total expenses reimbursable to the groundwater sustainability agency for providing the report among the parties in an amount, and in a manner, that the court deems equitable.
(3)During the pendency of the report provided pursuant to paragraph (1), upon a noticed motion by a groundwater sustainability agency, and following a hearing by the court after at least 10 days' notice to the parties, the court may order such interim or partial payments of the expense to be made by the parties.
(4)A report provided by a groundwater sustainability agency pursuant to paragraph (1) shall be prima facie evidence of the physical facts found in the report, but the court shall hear evidence that may be offered by any party to rebut the report or the prima facie evidence.
(e)This section does not limit the authority of the court to make a reference pursuant to Chapter 1 (commencing with Section 2000) of Part 3 of Division 2 of the Water Code.
(f)This section does not limit the authority to appoint a watermaster pursuant to Chapter 3 (commencing with Section 4050) of Part 4 of Division 2 of the Water Code or any other law.
Plain-English Summary
Comprehensive adjudications often need more technical fact-gathering than a judge alone can manage. Subdivision (a) lets the court appoint one or more special masters to investigate technical and legal issues (compiling findings under § 846), conduct joint factfinding with the parties, develop preliminary injunction proposals under § 847, and handle other tasks the court assigns.
Subdivision (b) has the court fix the special master's compensation and allocate it equitably among the parties, with authority to waive a party's payment obligation for good cause. Subdivision (c) lets the court ask the State Water Resources Control Board or the Department of Water Resources to recommend or vet candidates for the role.
Subdivision (d) addresses a particular gap: parties who haven't appeared in the case. In a basin with an approved groundwater sustainability plan, the court can request that the responsible agency prepare a technical report quantifying the groundwater use of non-appearing parties — including exempted or separately treated claimants, parties outside the court's jurisdiction, and parties in or approaching default. The agency isn't paid a fee for this but is reimbursed its actual expenses, allocated equitably by the court, with interim payments available on motion after notice. The resulting report serves as prima facie evidence of the facts it finds, though any party may offer evidence to rebut it. The remaining subdivisions clarify that this section doesn't limit the court's separate authority to refer matters to the State Water Resources Control Board or to appoint a watermaster under the Water Code.
Frequently Asked Questions
What can a special master do in a comprehensive adjudication?
Investigate technical and legal issues, conduct joint factfinding, develop a preliminary injunction proposal, and perform other tasks the court assigns.
Who pays the special master?
The parties, in an amount and manner the court deems equitable, though the court may waive a party's obligation for good cause.
What is the groundwater sustainability agency's technical report about?
It quantifies and describes the groundwater use of parties who haven't otherwise appeared before the court, including exempted, out-of-jurisdiction, or defaulting parties.
Is that agency report treated as conclusive?
No. It's prima facie evidence of the facts it finds, but the court must hear evidence any party offers to rebut it.
Amendment History
Amended by Stats 2025 ch 643 (AB 1466),s 4, eff. 1/1/2026. Added by Stats 2015 ch 672 (AB 1390),s 1, eff. 1/1/2016.
Source & verification. Section text is reproduced verbatim from
the Deering's California Codes Annotated / vLex. Enacted by the California Legislature.
Last verified July 28, 2026.
· Official source
Also known as:special master groundwater adjudication california