2019 California Standards for Accessible Design Guide (effective January 1, 2020 with July 1, 2021 amendments)

1010.1.5 Floor elevation.

There shall be a floor or landing on each side of a door. Such floor or landing shall be at the same elevation on each side of the door. Landings shall be level except for exterior landings, which are permitted to have a slope not to exceed 0.25 unit vertical in 12 units horizontal (2-percent slope).

Exceptions:

1. Doors serving individual dwelling units in Groups R-2 and R-3 where the following apply:

     1.1 A door is permitted to open at the top step of an interior flight of stairs, provided that the door does not swing over the top step.

     1.2 Screen doors and storm doors are permitted to swing over stairs or landings.

2. Exterior doors as provided for in Section 1003.5, Exception 1, and Section 1022, which are not on an accessible route.

3. In Group R-3 occupancies not required to be adaptable or accessible, the landing at an exterior doorway shall be not more than 7¾ inches (197 mm) below the top of the threshold, provided the door, other than an exterior storm or screen door, does not swing over the landing.

4. Variations in elevation due to differences in finish materials, but not more than ½ inch (12.7 mm).

5. Exterior decks, patios or balconies that are part of adaptable or accessible dwelling units, have impervious surfaces and that are not more than 4 inches (102 mm) below the finished floor level of the adjacent interior space of the dwelling unit. See also Chapter 11A, Section 1132A.4.

6. Doors serving equipment spaces not required to be adaptable or accessible and serving an occupant load of five or less shall be permitted to have a landing on one side to be not more than 7 inches (178 mm) above or below the landing on the egress side of the door.