Start with 1 unit per 50 guests for a 4-hour event.
Add 1 unit per 100 guests for each extra 4 hours.
Add 1 unit for every 4 you already counted.
Add 1 handwashing station per 4 toilets.
OSHA: 1 toilet for 20 or fewer workers; 1 seat and urinal per 40 above that.
Kingston Portable Toilets Rental, St. Charles, MO. Phones answered Mon–Sat, 7 a.m.–7 p.m..