How Many Porta Potties Do I Need?
Use the calculator for events, the OSHA table for job sites, and the worked examples to check your math.
How many porta potties per guest at an event?
Plan one standard porta potty per 50 guests for an event of up to 4 hours. Add half again for each extra block of 4 hours, add one unit when alcohol is served, and make one unit accessible if a guest uses a wheelchair. Add one hand-wash station per 100 guests when food is served.
Assumptions: GearReady dispatch rule of one standard unit per 50 guests for 4 hours. Accessible-unit rule from the 2010 ADA Standards, section 213.2 (5 percent of each cluster, at least one).
Worked example: how many units for a 150-guest wedding?
A 150-guest wedding lasting 6 hours with a bar needs 6 units. Start with 150 ÷ 50 = 3 units. The event runs 2 hours past 4, so add half of 3, rounded up: 2 units. Alcohol is served, so add 1. Total: 6 units, with one wheelchair-accessible unit among them.
How many porta potties does a construction crew need?
A construction crew of 20 or fewer workers needs at least one toilet under OSHA 29 CFR 1926.51. Above 20 workers, OSHA requires one seat and one urinal per 40 workers. For comfort with weekly service, plan one standard unit per 10 workers on a 40-hour week.
| Workers on site | OSHA minimum (29 CFR 1926.51 Table D-1) | What we recommend |
|---|---|---|
| 1–10 | 1 toilet | 1 standard unit, serviced weekly |
| 11–20 | 1 toilet | 2 standard units, serviced weekly |
| 21–40 | 1 seat and 1 urinal per 40 workers | 3–4 standard units with urinals |
| 41–80 | 2 seats and 2 urinals | 5–8 units, or twice-weekly service |
| 200+ | 1 seat and 1 urinal per 50 workers | Custom plan with daily service |
Legal minimum from OSHA 29 CFR 1926.51(c). Our recommendation assumes one unit per 10 workers on a 40-hour week with weekly service. Confirm site rules with your general contractor.
How many porta potties does a farm crew need?
A farm crew doing hand labor in the field needs one toilet and one hand-washing facility for every 20 workers under OSHA 29 CFR 1928.110, placed within a quarter-mile walk of where the crew works. A crew of 30 pickers needs two toilets and two hand-wash stations.
More questions: how many do i need?
Do I need a porta potty if guests can use the house bathroom?
For more than 30 guests, one house bathroom backs up fast and guests track through your home. One outdoor unit for every 50 guests takes the pressure off.
Should I get separate units for men and women?
For 100 or more guests, labeling one unit for men with a urinal-heavy layout shortens lines. Small events do not need it.
Does a restroom trailer replace several porta potties?
A 2-station restroom trailer covers about 100 guests over 5 to 6 hours, the same as two or three porta potties.
Next: event setups and construction setups
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