RCW 35.43.080
RCW 35.43.080: Ordinance—Creation of district.
Every ordinance ordering a local improvement to be paid in whole or in part by assessments against the property specially benefited shall describe the improvement and establish a local improvement district to be known as "local improvement district No. . . . .," or a utility local improvement district to be known as "utility local improvement district No. . . . ." which shall embrace as nearly as practicable all the property specially benefited by the improvement.