How many porta potties do I need? Enter guests and hours, then adjust for alcohol, kids, and accessible units.
Reviewed by Danielle, owner · Updated
The 5 answers you need before you call
Boise · 30 towns · 10 countiesPlan 1 standard porta potty per 50 guests for an event up to 4 hours. Events lasting 4 to 8 hours use guests ÷ 40. For all-day events over 8 hours, divide by 30. Always round up. A 100-guest party for 3 hours needs 2 units.
This is our recommended method, based on common portable sanitation industry charts. It is a planning guide, not a law.
| Guests | Up to 4 hours (÷ 50) | 4–8 hours (÷ 40) | Over 8 hours (÷ 30) |
|---|---|---|---|
| 25 | 1 | 1 | 1 |
| 50 | 1 | 2 | 2 |
| 75 | 2 | 2 | 3 |
| 100 | 2 | 3 | 4 |
| 150 | 3 | 4 | 5 |
| 200 | 4 | 5 | 7 |
| 250 | 5 | 7 | 9 |
| 300 | 6 | 8 | 10 |
| 400 | 8 | 10 | 14 |
| 500 | 10 | 13 | 17 |
Count everyone who will be on site over the whole event, including staff and vendors.
Alcohol raises restroom use. Add 1 unit for every 4 units on the chart, with a minimum of 1. Make the same addition when guests are mostly women or kids, such as a bridal shower or school event. If both apply, add both. A 4-unit wedding with a bar becomes 5 units.
| Units from the chart | Add for alcohol | Add for mostly women or kids |
|---|---|---|
| 1–7 | +1 | +1 |
| 8–11 | +2 | +2 |
| 12–15 | +3 | +3 |
| 16–19 | +4 | +4 |
Boise summers average 92.7°F in July. Guests drink more water and beer in the heat, so do not skip this step for an afternoon event. See our summer heat porta potty tips.
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The 2010 ADA Standards call for at least 5% of portable toilets in each cluster to be accessible. In practice that means at least 1 accessible unit per cluster. A cluster of 1 to 20 units needs 1, and a cluster of 21 to 40 needs 2. Each accessible unit needs a 60-inch turning circle.
| Units in one cluster | Accessible units |
|---|---|
| 1–20 | 1 |
| 21–40 | 2 |
| 41–60 | 3 |
The accessible unit counts toward your total. It replaces a standard unit rather than adding one. Units used only by construction workers are exempt under ADA rule 203.2.
Our ADA class units, such as the PolyJohn We'll Care III, have a ground-level floor. Each has a 60-inch turning circle. Details are on the ADA porta potty rental page.
Plan 1 two-sink hand-wash station for every 4 toilets when food is served. Round to the nearest whole station, with a minimum of 1. Five toilets need 1 station, and 17 toilets need 4. A PolyJohn Bravo station handles nearly 350 washes per fill.
| Toilets | Hand-wash stations |
|---|---|
| 1–5 | 1 |
| 6–9 | 2 |
| 10–13 | 3 |
| 14–17 | 4 |
| 18–21 | 5 |
Set at least one station beside the toilets and one near the food line at large events. Learn more about hand washing station rental.
OSHA rule 29 CFR 1926.51(c) sets toilet counts for construction. Up to 20 workers, one toilet meets the table. A crew over 20 needs 1 seat and 1 urinal per 40 workers. Crews of 200 or more need 1 seat and 1 urinal per 50 workers.
| Number of workers | Minimum facilities (Table D-1) |
|---|---|
| 20 or fewer | 1 toilet |
| 20 or more | 1 toilet seat and 1 urinal per 40 workers |
| 200 or more | 1 toilet seat and 1 urinal per 50 workers |
A standard PolyJohn PJN3 class unit has both a seat and a urinal. Crews over 10 people, or sites with heavy use, often add a second weekly service. Read the full OSHA toilet requirements for Idaho construction.
OSHA rule 29 CFR 1928.110 covers farms with 11 or more hand laborers in the field on any day. The farm needs 1 toilet and 1 handwashing facility for each 20 workers or fraction of 20. A crew of 35 needs 2 toilets and 2 hand-wash stations.
See farm porta potty rental for crew pricing and field placement.
These 3 examples use the same steps. Divide guests by the hours rule, round up, then add for alcohol or kids. Next, make 1 unit per cluster accessible and add hand-wash stations at 1 per 4 toilets. A 150-guest wedding with a bar ends at 5 units.
Price your count with the porta potty rental cost guide.
Enter your guest count and event length. The calculator divides guests by 50, 40 or 30 depending on hours, rounds up, adds whole units for alcohol or a mostly women and kids crowd, then shows how many should be wheelchair-accessible and how many hand-wash stations to add.
One standard unit serves about 50 guests for an event up to 4 hours. For 4 to 8 hours, plan on 40 guests per unit. For all-day events, plan on 30. Alcohol or a crowd of mostly kids lowers those numbers.
For 200 guests over about 5 hours, the chart calls for 5 units. A fair approach is to count each working indoor restroom as one unit. That leaves 3 to rent. Add 1 more if the bar is open.
Count everyone who comes over the whole event, not the peak crowd. For 75 guests across 4 hours or less, the chart gives 2 units. One unit works for about 50 guests in that time.
Fifty guests for up to 4 hours needs 1 standard unit. Add a hand-wash station if food is served. If drinks are flowing or most guests are kids, plan on 2 units so lines stay short.
Alcohol adds 1 unit for every 4 on the chart, with a minimum of 1. A 50-guest, 4-hour party goes from 1 unit to 2. A 150-guest, 5-hour wedding goes from 4 units to 5.
Treat a shelter as an all-day event: 460 ÷ 30 = 15.3, so plan 16 units. Make at least 1 per cluster wheelchair-accessible. Add 4 hand-wash stations, and schedule extra service visits for heavy daily use.
Add 1 unit for every 4 on the chart, with a minimum of 1. Bridal showers, school events, and kids' sports days fit this rule. A 100-guest bridal shower for 3 hours goes from 2 units to 3.
Official sources: OSHA 29 CFR 1926.51 Table D-1 · OSHA 29 CFR 1928.110 field sanitation · U.S. Access Board guide to toilet rooms
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