The most common rule of thumb for events is one portable toilet per 50 guests for a 4-hour event. Longer events, food and drinks, and job sites change the math. Here is how to figure out how many porta potties you need, plus the OSHA and ADA rules that apply.
How many porta potties for an event?
Starting from the one-per-50-guests guideline for a 4-hour event:
| Guests | Standard units (4-hour event) |
|---|---|
| Up to 50 | 1 |
| 100 | 2 |
| 250 | 5 |
| 500 | 10 |
| 1,000 | 20 |
Add more units when:
- The event runs longer than 4 hours, or spans multiple days
- Food, beer, or other beverages are served
- Guests arrive in waves, such as halftime or an intermission
For multi-day festivals, add mid-event service so units are pumped, cleaned, and restocked between days. Tell us your headcount, event hours, and whether food and drinks will be served, and we will recommend the right number.
ADA-accessible units for public events
Under the 2010 ADA Standards, where single-user portable toilets are clustered at one location, at least 5% of the units in each cluster, and no fewer than one, must be accessible and marked with the International Symbol of Accessibility. Units used only by construction workers on a construction site are exempt. (Source: U.S. Access Board guide to toilet rooms.)
Many permitted public events in South Carolina require ADA units, so plan at least one per cluster even for small gatherings.
How many porta potties for a construction site?
OSHA sets the minimum for construction job sites in 29 CFR 1926.51, Table D-1:
| Number of workers | Minimum facilities |
|---|---|
| 20 or fewer | 1 |
| 20 or more | 1 toilet seat and 1 urinal per 40 workers |
| 200 or more | 1 toilet seat and 1 urinal per 50 workers |
The requirement does not apply to mobile crews who have transportation readily available to nearby toilet facilities. On multi-story jobs, crane toilets can be lifted to upper floors so crews do not lose time going up and down.
Don’t forget hand washing
Hand wash stations and hand sanitizer stations can be rented on their own or added to any order. Pair them with your units at food events, weddings, and job sites.
How often are the units serviced?
Standard rentals include weekly service: pumping, cleaning, deodorizing, and restocking. High-traffic sites can request service two or three times a week, and event rentals include setup before and pickup after, with mid-event service for multi-day events.
Frequently asked questions
How many porta potties do I need for 100 guests?
For a 4-hour event, plan on 2 standard units for 100 guests, plus at least one ADA-accessible unit if the event is open to the public. Add more for longer events or if alcohol is served.
How many portable toilets does OSHA require on a job site?
OSHA requires 1 facility for 20 or fewer workers, 1 toilet seat and 1 urinal per 40 workers for 20 or more, and 1 toilet seat and 1 urinal per 50 workers for 200 or more.
Do I need an ADA porta potty for my event?
If portable toilets are provided for the public, the 2010 ADA Standards call for at least 5% of the units in each cluster, and no fewer than one, to be accessible.
Can I rent a hand wash station without a porta potty?
Yes. Hand wash and hand sanitizer stations are available as standalone rentals or as add-ons.
Get local details for porta potty rental in Sumter, SC and porta potty rental in Columbia, SC, or see all units on our portable toilet rentals page.
Ready to book or have a question? Call A Mobile Storage at (803) 773-5439 or request a quote online. We are a family-owned company based at 1021 N. Main Street in Sumter, SC.