How Many Porta Potties Do I Need?
Updated October 11, 2026
You need 1 standard porta potty for every 50 guests at an event of up to 4 hours. Add 1 unit per 100 guests for events longer than 4 hours, and 1 unit per 100 guests if alcohol is served. Construction sites follow OSHA Table D-1, and public events need at least 5% accessible units.
Method: Roy Rental Works planning counts, ADA 213.2 and OSHA Table D-1. Planning guide, not legal advice.
How many porta potties do I need for an event?
An event needs 1 porta potty per 50 guests for up to 4 hours by our planning method. A 100-guest, 4-hour party needs 2 units. A 100-guest, 6-hour party needs 3 units: 2 for the guests plus 1 because the party runs past 4 hours. A bar adds 1 more unit per 100 guests.
| Guests | Up to 4 hrs | Over 4 hrs | Over 4 hrs + alcohol | Hand wash stations |
|---|---|---|---|---|
| 50 | 1 | 2 | 3 | 1 |
| 100 | 2 | 3 | 4 | 1 |
| 150 | 3 | 5 | 7 | 2 |
| 200 | 4 | 6 | 8 | 2 |
| 300 | 6 | 9 | 12 | 3 |
| 500 | 10 | 15 | 20 | 5 |
| 1,000 | 20 | 30 | 40 | 10 |
Worked example: a 150-guest wedding with a bar
- 150 guests ÷ 50 = 3 units.
- The reception runs 5 hours, so add 1 unit per 100 guests: 150 ÷ 100 = 1.5, round up to 2. Total 5.
- A bar is open, so add 2 more. Total 7 units.
- 7 units ÷ 4 = 1.75, round up: 2 hand wash stations.
How many accessible porta potties does an event need?
Public events need at least 5% of the portable toilets in each cluster to be wheelchair-accessible, and never fewer than 1, under the 2010 ADA Standards section 213.2. A cluster of 12 units needs 1 accessible unit. Two clusters of 12 units each need 1 accessible unit in each cluster.
Official text: 2010 ADA Standards for Accessible Design, 213.2. See our wheelchair-accessible units.
How many porta potties does a construction site need?
OSHA 29 CFR 1926.51(c) Table D-1 sets the minimum: 1 toilet for 20 or fewer workers, 1 seat and 1 urinal per 40 workers for 20 or more, and 1 seat and 1 urinal per 50 workers for 200 or more. Roy Rental Works recommends 1 standard unit per 10 workers on a 40-hour week with weekly service.
| Workers | OSHA minimum | Our recommendation |
|---|---|---|
| 10 | 1 toilet | 1 unit |
| 20 | 1 toilet | 2 units |
| 35 | 1 seat + 1 urinal | 4 units |
| 60 | 2 seats + 2 urinals | 6 units |
| 120 | 3 seats + 3 urinals | 12 units |
| 250 | 5 seats + 5 urinals | 25 units |
Official text: OSHA 29 CFR 1926.51. More detail in our construction porta potty guide.
Does Richland County have its own event restroom rule?
The Richland County temporary event application lists minimum ratios for outdoor events: 1 toilet per 75 men and 1 per 40 women for up to 1,500 guests, plus sinks at 1 per 200 men and 1 per 150 women. The county minimum is often lower than our planning count, so most hosts plan above it.
Source: Richland County Temporary Event Application (PDF). Other towns have their own rules — see event permit restroom rules in the Midlands.
When should I rent more porta potties than the chart says?
Rent more porta potties than the chart says when most guests are women or children, when guests arrive all at once at a break or halftime, when it is hot, when units sit far apart, or when there is no other restroom on site. Add 1 unit for each of these that applies.
Sizing questions
How many porta potties for 100 guests?
2 standard units cover 100 guests for up to 4 hours. Plan 3 for a longer event and 4 if alcohol is served over more than 4 hours.
How many porta potties for 200 people?
4 standard units cover 200 people for up to 4 hours. Longer events with a bar need 8.
Do kids count as guests?
Count children as full guests. Kids use restrooms often and take longer, so they add to lines.
Can I rent fewer units and pay for a mid-event service?
A mid-event service empties and restocks the same units, so it helps long events. It does not shorten lines, so keep the base count for the crowd size.
Does a restroom trailer count the same as porta potties?
Count each trailer stall as 1 unit. A 2-stall trailer covers about 100 guests for 4 hours.