Wash. Admin. Code § 173-360A-0140
In order to fully implement this chapter, and to protect surface and groundwater resources that may cross jurisdictional boundaries, the department may negotiate and enter into cooperative agreements with Indian tribal governments, adjacent states, and Canadian governmental agencies. Such cooperative agreements do not affect the regulatory jurisdiction of any party thereto with regard to any civil or criminal matters otherwise exercised by any party. Intergovernmental agreements must further the purpose of this chapter, serve to establish a framework for intergovernmental coordination and cooperation, and serve to minimize duplication and efficiently utilize program resources to manage underground storage tanks and protect surface and groundwater resources.
Wash. Admin. Code § 173-360A-0140