Code Civ. Proc., § 329

The time within which an action for the foreclosure of a lien securing an assessment against real property for street improvements, the proceedings for which are prescribed by legislation of any political unit other than the state, may be commenced, shall be two years from and after the date on which the assessment, or any bond secured thereby, or the last installment of the assessment or bond, shall be due, or, as to existing rights of action not heretofore barred, one year after the effective date hereof, whichever time is later. After that time, if the lien has not been otherwise removed, the lien ceases to exist and the assessment is conclusively presumed to be paid. The official having charge of the records of the assessment shall mark it “Conclusively presumed paid,” if, at the expiration of the time within which such action might be brought he has received no written notice of the pendency of the action.