Window wells must:
- Allow the rescue window to open fully.
- Provide 9 square feet of "floor area," with a minimum dimension of 36 inches in width and in length.
- Contain a permanently affixed ladder or steps for climbing out if the window well depth exceeds 44 inches in depth. The ladder must be at least 12 inches wide and project no less than 3 inches from the window well. It cannot be obstructed by the open window or encroach on the required window well dimensions by more than 6 inches.
- If located under a deck or porch, the top of the window well must be more than 4 feet from the bottom of the deck or porch joists
- Have a guardrail around the egress well if an egress window well is adjacent to a walkway or stoop and is more than 30 inches deep.
Window wells may be made of rust-resistant metal, treated wood, wood naturally resistant to decay, concrete, masonry, or plastic. Some window well designs have steps built or molded into them. Covers are permitted.