Cal. Evidence Code § 601 : California Evidence Code — Burden Of Proof; Burden Of Producing Evidence; Presumptions And Inferences — Presumptions And Inferences — General — Conclusive or rebuttable Date: 31 Aug 2016 TEXT PDF Current through the 2016 Legislative Session A presumption is either conclusive or rebuttable. Every rebuttable presumption is either (a) a presumption affecting the burden of producing evidence or (b) a presumption affecting the burden of proof. Ca. Evid. Code § 601