What is Quantum Meruit in California

What is the legal doctrine of quantum meruit in California?

To recover on a claim for the reasonable value of services under a quantum meruit theory, a plaintiff must establish that: (1) defendant requested plaintiff perform services for the benefit of defendant, (2) that plaintiff formed the services as requested, (3) that defendant has not paid for the services and (4) the reasonable value of the services that were provided. Judicial Counsel of California, Civil Jury Instructions (CACI), No. 371; Ochs v. PacifiCare of California (2004) 115 Cal.App.4th 782, 794.