The maximum water depth for spas shall be 4 feet (1219 mm) measured from the design waterline except for spas that are designed for special purposes and approved by the authority having jurisdiction. The water depth for exercise spas shall not exceed 6 feet 6 inches (1981 mm) measured from the design waterline.
Where multi-level seating is provided, the maximum water depth of any seat or sitting bench shall be 28 inches (711 mm) measured from the design waterline to the lowest measurable point.
The slope of the floor shall not exceed 1 unit vertical in 12 units horizontal (8.3 percent slope). Where multi-level floors are provided, the change in depth shall be indicated.