Sizing guide
How Many Porta Potties Do I Need?
A calculator plus the exact tables we use for events, weddings and job sites, with OSHA and ADA rules cited. Whole numbers only.
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How many porta potties do you need for your event or site?
You need 1 porta potty per 50 guests for an event up to 4 hours, 1 per 35 for 5 to 8 hours and 1 per 25 for longer. Add 1 unit for every 4 when alcohol is served. Job sites need 1 per 10 workers for weekly service. Use the calculator for your numbers.
How many porta potties for an event, by guests and hours?
An event with 150 guests needs 3 porta potties for up to 4 hours, 5 for 5 to 8 hours, and 6 for 9 hours or more. Alcohol adds 1 unit for every 4: if the table says 5, add 2 for a total of 7. These are our planning numbers, based on the common 1-per-50-for-4-hours industry guideline.
| Guests | Up to 4 hrs | 5–8 hrs | 9+ hrs | 5–8 hrs with alcohol |
|---|---|---|---|---|
| 25 | 1 | 1 | 1 | 2 |
| 50 | 1 | 2 | 2 | 3 |
| 75 | 2 | 3 | 3 | 4 |
| 100 | 2 | 3 | 4 | 4 |
| 150 | 3 | 5 | 6 | 7 |
| 200 | 4 | 6 | 8 | 8 |
| 300 | 6 | 9 | 12 | 12 |
| 500 | 10 | 15 | 20 | 19 |
How many porta potties does OSHA require on a job site?
OSHA 29 CFR 1926.51(c) Table D-1 requires 1 toilet for 20 or fewer workers, 1 toilet seat and 1 urinal per 40 workers for 20 to 199 workers, and 1 seat and 1 urinal per 50 workers for 200 or more. A standard porta potty has 1 seat and 1 urinal, so a 60-worker crew needs at least 2 units by law.
| Workers | OSHA legal minimum | Our recommendation |
|---|---|---|
| 1–20 | 1 toilet | 1 per 10 workers |
| 20–199 | 1 seat + 1 urinal per 40 | 1 per 10 workers |
| 200+ | 1 seat + 1 urinal per 50 | 1 per 10 workers, or twice-weekly service |
Read the rule at osha.gov. Farms follow 29 CFR 1928.110: 1 toilet and 1 hand washing facility per 20 workers within a quarter-mile walk.
How many wheelchair-accessible porta potties are required?
The 2010 ADA Standards, section 213.2, require at least 5 percent of portable toilets in each cluster to be accessible, with a minimum of 1. A cluster of 8 units needs 1 accessible unit; a cluster of 30 needs 2. Each accessible unit needs a 60-inch diameter turning space in front of the door.
Rule text: 2010 ADA Standards for Accessible Design. See wheelchair-accessible unit specs.
How many hand washing stations should you add?
Add 1 hand washing station for every 4 porta potties at events with food, plus 1 at each food vendor area. On job sites, 1 two-sink station covers about 10 workers. Washing facilities are required by OSHA 1926.51(f) where workers handle paints, coatings or other contaminants.
Worked example: a 180-guest ranch wedding near Mancos
A 180-guest ranch wedding near Mancos lasting 6 hours with a bar needs 8 restrooms. The table gives 6 units for 180 guests at 5 to 8 hours (180 ÷ 35 = 5.1, rounded up to 6). Alcohol adds 2 (6 ÷ 4 = 1.5, rounded up). Swap 2 units for one two-stall trailer if power is on site, and add 2 hand washing stations near food.
Sizing questions
How many porta potties do I need for 100 guests?
100 guests need 2 porta potties for an event up to 4 hours, 3 for 5 to 8 hours, and 4 for a longer day. Add 1 unit if alcohol is served.
How many porta potties do I need for 200 guests?
200 guests need 4 porta potties for up to 4 hours and 6 for 5 to 8 hours. With a bar, add 1 unit for every 4, so a 6-hour event with alcohol needs 8.
Do women need more porta potties than men?
Women take longer per visit, so events with mostly women guests should add about 1 unit for every 4. Men's urinals inside standard units help keep lines short on the men's side.
How many porta potties for 10 workers?
OSHA requires at least 1 toilet for 20 or fewer workers. We recommend 1 standard unit per 10 workers with weekly service, so 10 workers need 1 unit.
How many porta potties for farm workers?
OSHA 29 CFR 1928.110 requires 1 toilet and 1 hand washing facility per 20 field workers, within a quarter-mile walk of where they work. Crews spread across large fields may need more units to stay inside that distance.
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