Rule 3.855.Impartiality, conflicts of interest, disclosure, and withdrawal
Division 8. Alternative Dispute Resolution · Chapter 3. General Rules Relating to Mediation of Civil Cases · Article 2. Rules of Conduct for Mediators in Court-Connected Mediation Programs for Civil Cases · Last amended 2007 · Last verified July 29, 2026
Full Text of Rule 3.855
Plain-English Summary
Impartiality is the backbone of a mediator’s credibility, and Rule 3.855 builds a full system around it: disclose, then let the parties react, then act on that reaction. The mediator’s baseline duty is simple to state and hard to police from the outside — stay impartial toward everyone in the room. To make that duty enforceable, the rule requires the mediator to actively look for anything that could reasonably make someone question that impartiality: past or current business ties, financial interests, personal relationships, or any of the circumstances that would require a judge to step aside from a case under Code of Civil Procedure section 170.1. This disclosure duty does not end once the mediation begins — it runs continuously, and new conflicts have to be disclosed as soon as the mediator becomes aware of them.
What happens after disclosure depends on how the parties react. If nobody objects or raises a concern, the mediator can proceed. If someone raises a question, the mediator has to address it, and if that resolves the concern without a formal objection, the mediation can continue. But a real objection changes things: in a two-party mediation, a party’s objection after disclosure forces the mediator to withdraw. When more than two parties are involved, the mediator has more flexibility to continue with the parties who did not object, as long as doing so does not run afoul of another rule, a law, or a local program requirement.
Some circumstances override even a party’s willingness to proceed. If the mediator truly cannot stay impartial, or if continuing would threaten the integrity of the court or the mediation process itself, the mediator must decline or withdraw regardless of whether the parties consent.
Advisory Committee Comment
The following comment is published by the Judicial Council of California alongside the rule itself — not commentary from this site.
Subdivision (b). This subdivision is intended to provide parties with information they need to help them determine whether a mediator can conduct the mediation impartially. A mediator’s overarching duty under this subdivision is to make a “reasonable effort” to identify matters that, in the eyes of a reasonable person, could raise a question about the mediator’s ability to conduct the mediation impartially, and to inform the parties about those matters. What constitutes a “reasonable effort” to identify such matters varies depending on the circumstances, including whether the case is scheduled in advance or received on the spot, and the information about the participants and the subject matter that is provided to the mediator by the court and the parties. The interests, relationships, and affiliations that a mediator may need to disclose under (b)(1)(A) include:
(1) prior, current, or currently expected service as a mediator in another mediation involving any of the participants in the present mediation; (2) prior, current, or currently expected business relationships or transactions between the mediator and any of the participants; and (3) the mediator’s ownership of stock or any other significant financial interest involving any participant in the mediation. Currently expected interests, relationships, and affiliations may include, for example, an intention to form a partnership or to enter into a future business relationship with one of the participants in the mediation. Although (b)(1) specifies interests, relationships, affiliations, and matters that are grounds for disqualification of a judge under Code of Civil Procedure section 170.1, these are only examples of common matters that reasonably could raise a question about a mediator’s ability to conduct the mediation impartially and, thus, must be disclosed. The absence of particular interests, relationships, affiliations, and section 170.1 matters does not necessarily mean that there is no matter that could reasonably raise a question about the mediator’s ability to conduct the mediation impartially. A mediator must make determinations concerning disclosure on a case-by-case basis, applying the general criteria for disclosure under (b)(1). Attorney mediators should be aware that under the section 170.1 standard, they may need to make disclosures when an attorney in their firm is serving or has served as a lawyer for any of the parties in the mediation. Section 170.1 does not specifically address whether a mediator must disclose when another member of the mediator’s dispute resolution services firm is providing or has provided services to any of the parties in the mediation. Therefore, a mediator must evaluate such circumstances under the general criteria for disclosure under (b)(1)—that is, is it a matter that, in the eyes of a reasonable person, could raise a question about the mediator’s ability to conduct the mediation impartially? If there is a conflict between the mediator’s obligation to maintain confidentiality and the mediator’s obligation to make a disclosure, the mediator must determine whether he or she can make a general disclosure of the circumstance without revealing any confidential information, or must decline to serve.
Frequently Asked Questions
What kinds of relationships must a mediator disclose?
Past, present, or reasonably expected personal, professional, or financial interests, relationships, and affiliations that could make a reasonable person question the mediator’s impartiality — including circumstances that would require a judge to be disqualified under Code of Civil Procedure section 170.1.
What happens if one party objects to the mediator after a disclosure?
In a two-party mediation, the mediator must withdraw. In a mediation with more than two parties, the mediator may continue with the parties who did not object, provided doing so does not violate another rule, the law, or a local program requirement.
Can a mediator continue if all parties agree to waive a conflict?
Not always. If the mediator cannot in fact maintain impartiality, or if continuing would jeopardize the integrity of the court or the mediation process, the mediator must decline or withdraw even if every party consents.
When does a mediator’s duty to disclose conflicts begin and end?
It is a continuing obligation that starts at the beginning of the mediation process and lasts through its completion. Disclosures must be made as soon as practical after the mediator learns of the matter, ideally before the first session and always within any deadline set by applicable rules or statutes.
Amendment History
Rule 3.855 amended and renumbered effective January 1, 2007; adopted as rule 1620.5 effective January 1, 2003.