What is the mandated distance between any two lavatories in a series installation?

The mandated distance between any two lavatories in a series installation is 30 inches. This requirement helps ensure that there is adequate space for users to comfortably access each lavatory. A distance of 30 inches allows for sufficient room to avoid crowding and promotes accessibility unless otherwise specified by local codes or regulations. The standard is rooted in considerations of practicality and comfort in public restrooms, catering to different users' needs while also ensuring compliance with health and safety standards.

While other distances such as 18 inches, 24 inches, or 31 inches may also be referenced in various contexts or specific projects, they do not meet the widely accepted standard of 30 inches for standard installations, making that the most appropriate answer for this question.