WAC 16-229-110
WAC 16-229-110. Primary containment of bulk liquid pesticides—Prohibition against underground storage
No person shall store liquid bulk pesticide, pesticide spills or rinsates in an underground storage container or surface impoundment, such as a lined pond or pit. A watertight catch basin or sump used for the temporary collection of rinsate or runoff from transfer and loading areas is exempt from this section.