Since answering this question from a reader whose employer was limiting her to three bathroom breaks a day unless she got written permission in advance, a commenter pointed out that OSHA rules are likely at play here.
OSHA — the Occupational Safety and Health Administration — says that prohibiting employees from using the bathroom outside of scheduled break times can create unhealthy working conditions … and while it doesn’t require that employees be given free and constant access to bathrooms, or that X breaks be allowed per hour/day, it does require that employees have reasonable access to bathrooms.
The agency notes: “It would be difficult to set a specific interval for breaks, because the need to use toilet facilities varies from person to person and even with respect to the same person. Some of the variables that can affect a worker’s need to urinate are: diet, stress, pregnancy, prostate health, other medical conditions, medication use, weather temperature (working in a cold environment makes people need to urinate more frequently), and the amount and type of fluid consumed. Also, in some workplaces the nature of the work or the tasks being performed may require constant worker coverage/attention. In such situations employers need flexibility in developing procedures that will allow all of their workers access to toilet facilities as needed. A specific schedule for breaks might not allow the flexibility needed to address all types of work situations.”
It’s also worth noting that the Fair Labor Standards Act requires that employees be paid for any break shorter than 20 minutes, so employers shouldn’t be requiring people to clock out to use the bathroom (assuming that you’re not taking more than 20 minutes for it).