Wash. Rev. Code § 54.16.120
A district may, by resolution, establish and define the boundaries of local assessment districts to be known as local utility district No. . . . ., for distribution, under the general supervision and control of the commission, of water for all purposes, public and private, including domestic use, irrigation, and electric energy, and for providing street lighting, or any of them, and in like manner provide for the purchasing, or otherwise acquiring, or constructing and equipping and maintaining and operating distribution systems for such purposes, and for extensions and betterments thereof, and may levy and collect in accordance with the special benefits conferred thereon, special assessments and reassessments on property specially benefited thereby, for paying the cost and expense thereof, or any portions thereof, as herein provided, and issue local improvement bonds or warrants or both to be repaid wholly or in part by collection of local improvement assessments. A district also may form local utility districts located entirely or in part outside its limits or the limits of the county in which the district is located to provide water, or sewer facilities if otherwise authorized under this title.
RCW 54.16.120
Assessments and charges against state lands: Chapter 79.44 RCW.
Local improvements, supplemental authority: Chapter 35.51 RCW.