A restroom trailer is a mobile sanitation unit designed to provide comfortable restroom facilities in outdoor or temporary locations. Unlike standard portable toilets, restroom trailers usually include flushing toilets, sinks, mirrors, lighting, ventilation, fresh water tanks and waste water tanks. They are commonly used for outdoor weddings, festivals, construction sites, private events, farm venues, parks and rental businesses. This guide explains what a restroom trailer is, how it works, where it is used and what buyers should consider before choosing one.