How many porta potties do I need?
Quick answer: plan 1 standard unit per 75 guests at peak for events up to about 4 hours, and add exactly 1 unit for every 4 if alcohol is served. On Texas job sites, OSHA’s minimum is 1 toilet for up to 20 workers and 1 seat plus 1 urinal per 40 above that (29 CFR 1926.51). Use the calculators below for your numbers.
Common answers
- 100 guests, 4 h
- 2 units
- + alcohol
- 3 units
- 250 guests, 6 h
- 4 units
- 500 guests, 8 h
- 10 units
- 16 workers
- 1 per sex (≥1 + 1)
- ADA
- 5% of cluster, min. 1
Events and job sites
Standard units by guests and hours
| Guests | 2 hrs | 4 hrs | 6 hrs | 8 hrs | 10 hrs |
|---|---|---|---|---|---|
| 50 | 1 | 1 | 1 | 1 | 2 |
| 100 | 2 | 2 | 2 | 2 | 3 |
| 150 | 2 | 2 | 3 | 3 | 4 |
| 200 | 3 | 3 | 3 | 4 | 5 |
| 300 | 4 | 4 | 5 | 6 | 8 |
| 400 | 6 | 6 | 6 | 8 | 10 |
| 500 | 7 | 7 | 8 | 10 | 13 |
| 750 | 10 | 10 | 12 | 15 | 19 |
| 1,000 | 14 | 14 | 15 | 20 | 25 |
| 1,500 | 20 | 20 | 23 | 30 | 38 |
| 2,000 | 27 | 27 | 30 | 40 | 50 |
Exact add-ons, no percentages to calculate
- Alcohol: table says 4 → order 5; says 8 → order 10; says 12 → order 15.
- Mostly female guests (e.g., a bridal shower): add 1 unit for every 4 in the table—urinals don’t help.
- Permanent restrooms on site: subtract 1 unit for every 2 working toilet fixtures guests can actually reach.
- Events over 8 hours: add 1 mid-event service visit.
- Two separate areas (e.g., ceremony and reception): put at least 1 unit in each.
Frequently asked questions
Where does the event formula come from?
It’s our planning method: the higher of (a) guests ÷ 75, which keeps lines short at peak, and (b) total expected uses (guests × hours × 0.5) ÷ 200 uses per 60-gallon tank. Alcohol adds 1 unit per 4. It is a planning guide, not a legal requirement.
Where does the construction number come from?
The legal minimum is OSHA 29 CFR 1926.51 Table D-1: 1 toilet for 20 or fewer workers, 1 seat and 1 urinal per 40 above that, 1 per 50 at 200 or more. Our weekly-service recommendation (about 10 workers per unit per 40-hour week) follows the ANSI Z4.3 guidance OSHA cites.
Do the numbers include accessible units?
The accessible count is part of the total, not extra: at least 5% of each cluster, minimum one, per 2010 ADA Standards §213.2.