A diaper changeing station must have operable parts within 34–48 inches, easy to use with one hand, with 30″ × 48″ clear floor space in front, and without blocking circulation when open. Federal law (Baby Changing Facilities Act of 2016) requires them in both men’s and women’s restrooms of federal public buildings, and many states extend this to other public facilities.
Additional Resource: https://www.ada.gov/law-and-regs/design-standards/standards-guidance/#top