Is a failure to exhaust an administrative remedy waived by the County?

The County also suggests that an assessment appeal is an administrative remedy and the taxpayer's failure to exhaust that remedy may be waived by the County regardless of section 80, subdivision (a)(5), citing Green v. City of Oceanside (1987) 194 Cal.App.3d 212, 239 Cal.Rptr. 470. In that case, the court held, in the context of an employment dispute, that a city could and did waive the defense of failure to exhaust administrative remedies because the doctrine of exhaustion was merely a procedural prerequisite and not an element of fundamental subject matter jurisdiction. (Id. at pp. 219-223, 239 Cal.Rptr. 470.)