Why do some porta potties have a urinal inside and some do not?

The urinal is an optional feature on standard portable toilets, not a standard part of the unit model. Some rental companies add urinals to units in their fleet to extend service intervals on male-dominated sites, as urinals reduce liquid waste volume in the holding tank. For your 12-person construction crew, OSHA 1926.51 requires only one toilet, so both units meet the minimum. The company likely sent one unit with a urinal and one without based on fleet availability or their internal tracking for units assigned to construction versus event rentals. It does not depend on the unit's age. The urinal-equipped unit may stay cleaner longer with the crew, but both will need weekly servicing. If the crew prefers the urinal, you can request that feature specifically on future rentals.

The rental company dispatches units based on availability and their fleet management system, which may prioritize urinal-equipped units for male-dominated sites like construction crews to reduce liquid waste and extend service intervals. Ray, the driver likely grabbed two units from the available stock without checking for urinals, as both meet OSHA 1926.51 for your 12-person crew. For future rentals, specify if you want a urinal; some companies charge extra for this feature due to the added cleaning and maintenance. Without a request, it's random which unit you get.