WAC 51-54A-5704
WAC 51-54A-5704. Storage
5704.2.11 Underground tanks. Underground storage of flammable and combustible liquids in tanks shall comply with Section 5704.2 and Sections 5704.2.11.1 through 5704.2.11.4.2. Corrosion protection shall comply with WAC 173-360-305 .