WAC 246-215-05300
WAC 246-215-05300. Materials — Approved (FDA Food Code 5-301.11)
Materials that are used in the construction of a mobile water tank, mobile food unit water tank, and appurtenances must be:
(1) Safe;
(2) Durable, corrosion-resistant and nonabsorbent; and
(3) Finished to have a smooth , easily cleanable surface.