How many porta potties do I need?
Short answer: one standard unit for every 75 people at the busiest hour of an event up to about four hours, plus one for every four if there is a bar. On a job site in Texas or New Mexico, OSHA requires one toilet for up to 20 workers, then one seat and one urinal per 40. The counters below do the math for your numbers.
Common results
- 100 people, 4 h
- 2 units
- Same, with a bar
- 3 units
- 300 people, 5 h
- 4 units
- 500 people, 8 h
- 10 units
- 45 workers
- 2 required
- Accessible
- 5% of a cluster, at least 1
Events and job sites
Standard units by crowd and hours
| People | 3 hrs | 5 hrs | 7 hrs | 9 hrs | 12 hrs |
|---|---|---|---|---|---|
| 40 | 1 | 1 | 1 | 1 | 2 |
| 80 | 2 | 2 | 2 | 2 | 3 |
| 125 | 2 | 2 | 3 | 3 | 4 |
| 175 | 3 | 3 | 4 | 4 | 6 |
| 250 | 4 | 4 | 5 | 6 | 8 |
| 350 | 5 | 5 | 7 | 8 | 11 |
| 450 | 6 | 6 | 8 | 11 | 14 |
| 600 | 8 | 8 | 11 | 14 | 18 |
| 800 | 11 | 11 | 14 | 18 | 24 |
| 1,200 | 16 | 16 | 21 | 27 | 36 |
| 1,600 | 22 | 22 | 28 | 36 | 48 |
Simple add-ons, no percentages
- Bar: chart says 4, order 5. Chart says 8, order 10. Chart says 12, order 15.
- Mostly women (a bridal shower, a quinceañera court party): add one for every four, since urinals go unused.
- Indoor restrooms guests can reach: subtract one unit for every two working fixtures.
- Longer than 8 hours: add a mid-event cleaning visit.
- Two separate areas, like a church ceremony and a backyard reception: at least one unit at each.
Questions about the counts
What is the event formula based on?
It is our planning method. We take the larger of two numbers: people ÷ 75, which keeps peak lines short, and people × hours × 0.5 ÷ 200, which is how many uses a 60-gallon tank absorbs. A bar adds one unit for every four. It is guidance, not a legal requirement.
What is the job-site number based on?
The required count is OSHA 29 CFR 1926.51 Table D-1, which applies in Texas and is adopted by New Mexico’s state plan. Our suggested count (about 10 workers per unit per 40-hour week) follows the ANSI Z4.3 benchmark OSHA cites.
Are accessible units on top of the total?
No, they are part of it. Make at least 5 percent of each cluster accessible, never fewer than one, per 2010 ADA Standards §213.2.
Does El Paso heat change the count?
Not the count, but it changes the cleaning. On long summer events, people drink more water and visit more often, so we add a service visit sooner than we would in March.