(a) In any action, regardless of who is the moving party, where the boundary of land patented or otherwise granted by the state is in dispute, or the validity of any state patent or grant dated before 1950 is in dispute, all parties shall have the duty to disclose to all opposing parties all nonprivileged relevant written evidence then known and available, including evidence against interest, relating to the above issues.
§ 2031.510.Land patented or granted by state; time to disclose
Title 4. Civil Discovery Act · Chapter 14. Inspection, Copying, Testing, Sampling, and Production of Documents, Electronically Stored · Article 3. Inspection and Production of Documents and Other Property in Specific Contexts · Enacted 2004 · no amendments on record · Last verified July 29, 2026
In one sentenceSection 2031.510 requires all parties in an action disputing the boundary of state-patented or state-granted land, or the validity of a pre-1950 state patent or grant, to disclose all known, nonprivileged, relevant written evidence, including evidence against interest, within 120 days after proof of service on all named defendants, and to keep disclosing later-discovered evidence.
Full Text of § 2031.510
(b) This evidence shall be disclosed within 120 days after the filing with the court of proof of service upon all named defendants. Thereafter, the parties shall have the continuing duty to make all subsequently discovered relevant and nonprivileged written evidence available to the opposing parties.
Plain-English Summary
Most discovery in this chapter waits for a party to ask; this section instead imposes an automatic, ongoing disclosure duty in a narrow category of land disputes. Whenever a case turns on the boundary of land patented or otherwise granted by the State of California, or on the validity of a state patent or grant issued before 1950, every party, regardless of which side filed the action, has to disclose to every opposing party all nonprivileged, relevant written evidence then known and available on those issues, including evidence that cuts against the disclosing party's own position.
That disclosure has a firm deadline: it has to happen within 120 days after proof of service on all named defendants is filed with the court. The duty does not end there, though; the parties carry a continuing obligation to make later-discovered relevant, nonprivileged written evidence available to the opposing side as it comes to light, reflecting how old land-patent disputes often depend on documents that turn up well after a case begins, from historical survey records to long-buried title chains.
Frequently Asked Questions
What kind of case triggers this disclosure duty?
An action disputing the boundary of land patented or granted by the State of California, or the validity of a state patent or grant dated before 1950.
What has to be disclosed?
All nonprivileged, relevant written evidence then known and available, including evidence against the disclosing party's own interest.
When is the initial disclosure due?
Within 120 days after proof of service on all named defendants is filed with the court.
Does the duty end after the initial 120-day disclosure?
No, the parties have a continuing duty to disclose later-discovered relevant, nonprivileged written evidence.
Amendment History
(Added by Stats.2004, c. 182 (A.B.3081), § 23, operative July 1, 2005.)
Source & verification. Section text is reproduced verbatim from
the West's Annotated California Codes / Thomson Reuters. Enacted by the California Legislature.
Last verified July 29, 2026.
· Official source
Also known as: state land patent boundary dispute disclosure californiapre-1950 state grant validity discovery duty