ARM 37.115.503
ARM 37.115.503. MATERIALS
Cite as Mont. Admin. R. 37.115.503
(1) Pools, spas, and other water features shall be constructed of concrete, steel, or other approved materials which are inert, stable, nontoxic, watertight, and enduring.
(2) Nontempered glass is prohibited in close proximity to any pool, spa, or other water feature.
(3) No wooden spa units are permitted.