A defendant may be equitably estopped from asserting a statutory or contractual limitations period as a defense if the defendant's act or omission caused the plaintiff to refrain from filing a timely suit and the plaintiff's reliance on the defendant's conduct was reasonable. (Lantzy v. Centex Homes (2003) 31 Cal.4th 363, 384-385 2 Cal. Rptr. 3d 655, 73 P.3d 517 (Lantzy); Vu v. Prudential Property & Casualty Ins. Co. (2001) 26 Cal.4th 1142, 1152-1153 113 Cal. Rptr. 2d 70, 33 P.3d 487 (Vu); Spray, Gould & Bowers v. Associated Internat. Ins. Co. (1999) 71 Cal.App.4th 1260, 1268-1269 84 Cal. Rptr. 2d 552 (Spray).) The act or omission must constitute a misrepresentation or nondisclosure of a material fact, rather than law. (Vu, supra, at p. 1152.) The defendant need not intend to deceive the plaintiff to give rise to an equitable estoppel. (Lantzy, supra, 31 Cal.4th at p. 384; Vu, supra, 26 Cal.4th at pp. 1152-1153.) "One aspect of equitable estoppel is codified in Evidence Code section 623, which provides that 'whenever a party has, by his own statement or conduct, intentionally and deliberately led another to believe a particular thing true and to act upon such belief, he is not, in any litigation arising out of such statement or conduct, permitted to contradict it.' But '"an estoppel may arise although there was no designed fraud on the part of the person sought to be estopped. To create an equitable estoppel, 'it is enough if the party has been induced to refrain from using such means or taking such action as lay in his power, by which he might have retrieved his position and saved himself from loss.' ... '... Where the delay in commencing action is induced by the conduct of the defendant it cannot be availed of by him as a defense.'"' " (Lantzy, supra, 31 Cal.4th at p. 384.) Equitable estoppel "rests firmly upon a foundation of conscience and fair dealing." (City of Long Beach v. Mansell (1970) 3 Cal.3d 462, 488 91 Cal. Rptr. 23, 476 P.2d 423.) "Professor Pomeroy emphasizes the broad equitable concepts underlying the doctrine in the following terms: 'Equitable estoppel in the modern sense arises from the conduct of a party, using that word in its broadest meaning as including his spoken or written words, his positive acts, and his silence or negative omission to do anything. Its foundation is justice and good conscience. Its object is to prevent the unconscientious and inequitable assertion or enforcement of claims or rights which might have existed or been enforceable by other rules of the law, unless prevented by the estoppel; and its practical effect is, from motives of equity and fair dealing, to create and vest opposing rights in the party who obtains the benefit of the estoppel.' (3 Pomeroy, Equity Jurisprudence (5th ed. 1941) 802, p. 180, fns. omitted.)" (Id. at p. 488, fn. 22.) "If one maintains silence when in conscience he ought to speak, equity will debar him from speaking when in conscience he ought to remain silent. " (3 Pomeroy, supra, 818, p. 250.) A nondisclosure is a cause of injury if the plaintiff would have acted so as to avoid injury had the plaintiff known the concealed fact. (Mirkin v. Wasserman (1993) 5 Cal.4th 1082, 1093 23 Cal. Rptr. 2d 101, 858 P.2d 568.)