It’s the most common question we get at Green Port-a-Jon: “How many units do I need?” The answer depends on a few key variables. Here’s a simple framework to help you plan.
The Basic Formula
For events with no alcohol service, the standard calculation is 1 portable restroom per 50 guests for every 4 hours of event time. If alcohol is being served, increase that ratio — plan for 1 unit per 40 guests instead.
For construction sites, OSHA requirements are your baseline (see our construction sanitation post for specifics). For disaster relief or utility work, volume and timeline drive the count.
Adjust for Event Duration
A 2-hour event can work with fewer units than a full-day festival. If your event runs 8+ hours, factor in that units will need servicing mid-event if the crowd is large. We can schedule mid-event pump-outs for multi-day events.
When in Doubt, Add One
Running out of restroom capacity at an event is one of those problems that creates immediate, visible complaints. The cost of one additional unit is small compared to the guest experience impact of long lines or overflow situations. When our customers call asking whether they should add another unit, our advice is almost always yes.
Don’t Forget Handwashing
If food is served or if your crowd includes children, standalone handwashing stations are worth adding. They reduce the load on portable restroom facilities and improve overall sanitation — especially important during peak illness seasons.
Get a Custom Quote
Every event is different. Tell us your guest count, event duration, location, and what’s being served, and we’ll put together the right sanitation plan for your specific situation. Call 843-319-0278 or contact us online — we’re happy to help you think it through.