Having two lavatories in a bathroom can be a luxury—especially when you have two people that need to use it at the same time. The thoughtful designer, however, might not realize that adding a second sink to a bathroom in multifamily housing can have other design implications, since multifamily dwellings are covered by the Fair Housing Act Accessibility Guidelines.
Requirement 7 of the section on Usable Bathrooms requires all fixtures in an Option A bathroom to have a clear floor space. For lavatories, the clear floor space can be positioned for a parallel approach, or a forward approach can be provided with the use of removable cabinets.
However, when there are multiple lavatories in an Option B bathroom (Specification B), only one must have clear floor space. As noted in the above figure, this would require parallel access to the bathtub (and 34” counters), but might be a good solution for adding a second lav.