Wash. Rev. Code § 90.48.264
In implementing this chapter and in participating in programs under the federal clean water act, the department may consult with the department of social and health services concerning standards for repair of existing, failing on-site sewage disposal systems that are adjacent to marine waters. By January 1, 1989, the department of social and health services shall propose rules for adoption by the state board of health identifying the standards for repair of existing, failing on-site sewage disposal systems at single-family residences that were legally occupied prior to June 9, 1988, and that are adjacent to marine waters. The rules may specify the design, operation and maintenance standards for such repaired systems so as to ensure protection of the public health, attainment of state water quality standards and the protection of shellfish and other public resources. The rules shall also provide that any proposed discharge to marine water shall be considered only if on-site sewage disposal systems are not feasible and that such discharges shall meet the requirements of this chapter and department of ecology regulations. The state board of health shall adopt such proposed rules unless the board finds modification or rejection of them necessary to protect the public health.
RCW 90.48.264