Whenever any system of improvement constructed under the provisions of this chapter results in benefit to the whole or any part of a public street or road, street or road bed or track thereof within the district, or will facilitate the construction or maintenance of any sewer system in any city or town within the district, the city, town or subdivision or any of them responsible for the maintenance of said public road, street or sewer, shall be liable for assessment for any or all district purposes.
RCW 86.09.523