If the owners fail to comply with the order issued by the board, or, if appealed, the order issued by the city council or the Kittitas County Superior Court, then, and in that event, the board may direct or cause such dwelling, building or structure to be repaired or demolished, as the order may require, and the costs of such shall be assessed against the real property upon which such costs were incurred, unless such amount is previously paid. The city treasurer shall determine the amount of the assessment due and owing and shall certify the same to the county treasurer, who shall enter the amount of such assessment upon the tax rolls against the property, all in the manner provided by law.