Portable Restrooms & Restroom Trailers

Michigan's construction safety rules call for 1 toilet for 1 to 20 employees, 2 for 21 to 40, and 1 more for each additional 40 employees or fewer. Toilets must be serviced and maintained on a regular basis.

It depends on attendance and how long the event runs. One national provider's chart lists 5 units for 500 people at a 4 hour event, adds 15 to 20 percent more units when food and drinks are served, and suggests at least one handwashing station per four restrooms.

Under the 2010 ADA Standards, where several single-user portable toilets are grouped in one spot, no more than 5 percent of the units in each group are required to be accessible, and accessible units must be marked with the International Symbol of Accessibility. Portable toilets used only by construction workers on a construction site are exempt. Ask the provider how many ADA units your order includes.

Ask how often units are serviced (some providers offer weekly or every-other-week service), whether delivery and pickup are included, and whether weekend or emergency service costs extra. For cold months, ask whether tanks get a winterization mix and whether extra service is recommended.