Employees of a private firm who, under the firm’s contract with the district, sorted recyclables from a conveyor belt at a county sanitary district-owned facility were employed to perform “public work” to which the prevailing wage law applied.  Lab. Code 1720(a)(2) defines public work to include work done for irrigation, utility and other similar districts.  This work for the sanitary district fell within that definition.  Public work for purposes of the prevailing wage law is not confined to work on construction projects.