Communications made and writings prepared “for the purpose of, in the course of, or pursuant to” mediation or a mediation consultation are ordinarily confidential, not discoverable and not admissible at trial.  This rule applies to all communications by participants before conclusion of the mediation that are materially related to it, regardless of whether they are made in the mediator’s presence.  Evidence Code §1119, 1121; Rojas v. Super. Ct. (Coffin) (2004) 33 C4th 407, 424, 15 CR3d 643, 655-656; Marriage of Kieturakis (2006) 138 CA4th 56, 61-62, 41 CR3d 119, 121-122; Eisendrath v. Super. Ct. (Rogers) (2003) 109 CAth 351, 364, 134 CR2d 716, 725.

The court in Kieturakis held that the mediation confidentiality rule is “broadly framed and strictly construed.” Kieturakis, supra 138 CA4th at 85, 41 CR3d at 140.
Unlike most evidentiary privileges, the mediation privilege cannot impliedly be waived by conduct (e.g., by making a claim that places confidential communications in issue). Eisendrath, supra, 109 CA4th at 362-363, 134 CR 2d at 723-724. The court in Eisendrath, specifically rejected the notion of extending the concept of implied waiver [found in other Evidence Code sections] to mediation confidentiality: “We conclude that the implied waiver provisions in section 910 et seq., by their plain language, are limited to the particular privileges enumerated therein. None of these waiver provisions refer to mediation confidentiality rights or the statutory scheme governing these rights. Furthermore, we may not extend these waiver provisions beyond their existing limits.” Eisendrath, supra, 109 CA4th at 363.

Mediation-related communications are generally shielded from disclosure unless all participants (including the mediator) expressly agree otherwise.  Evidence Code §1122(a)(1); Eisendrath, supra, 109 CA4th at 362-363, 134 CR 2d at 723-724.