For an event, plan on one porta potty per 50 guests for an event of up to four hours, and add units when the event runs longer or serves alcohol. On a California job site, Cal/OSHA requires at least one toilet for every 20 employees of each sex, plus one hand washing station per 20 workers.
Use the calculator below for your number, then send it to us with your date and address. Get a free quote or call (925) 222-5755.
How many porta potties do I need for an event?
Start with one unit per 50 guests for an event of up to four hours, then add for time, alcohol and a crowd that is mostly women. The table below is the rule of thumb I use when people call for a quote: add 25% past four hours, 50% past six and double it past eight, then add another 20% if alcohol is served. It counts every unit, including the ADA unit.
| Guests | Up to 4 hours | 4 to 6 hours | 6 to 8 hours | Over 8 hours |
|---|---|---|---|---|
| 50 | 1 / 2 | 2 / 2 | 2 / 2 | 2 / 3 |
| 100 | 2 / 3 | 3 / 3 | 3 / 4 | 4 / 5 |
| 150 | 3 / 4 | 4 / 5 | 5 / 6 | 6 / 8 |
| 200 | 4 / 5 | 5 / 6 | 6 / 8 | 8 / 10 |
| 300 | 6 / 8 | 8 / 9 | 9 / 11 | 12 / 15 |
| 500 | 10 / 12 | 13 / 15 | 15 / 18 | 20 / 24 |
These are planning numbers, not a law. If most of your guests are women, add about 20% to the table. The calculator does that for you when you answer yes. Some cities and counties set their own counts in event permits, and when they do, the permit wins. If your event runs past eight hours or over more than one day, ask about servicing during the event. A mid-event pump-out can keep a smaller number of units usable.
Our event porta potty rentals page covers delivery, pickup and the unit types we bring to parties, festivals and weddings.
How many porta potties does a construction site need?
In California, the legal minimum is one toilet per 20 employees of each sex, under Cal/OSHA Title 8, Section 1526. Crews of fewer than five can share one all-gender unit.
Federal OSHA has its own table in 29 CFR 1926.51, Table D-1: one toilet for 20 or fewer workers, one toilet seat and one urinal per 40 workers above that, and one per 50 once you pass 200. California’s rule is stricter, so follow the Cal/OSHA number on a California site.
The legal minimum is not always enough to keep a unit clean between weekly services. OSHA has pointed employers to the ANSI/PSAI Z4.3 servicing schedule as a guide, which works out to about one toilet per 10 people over a 40-hour week with weekly service. At Bay Area Sanitation, we recommend a little more: one unit per 8 workers. That is the rule of thumb the calculator uses, and it goes up for longer workdays.
| Workers | Cal/OSHA minimum | Federal OSHA minimum | Our recommendation | Hand wash stations |
|---|---|---|---|---|
| 1 to 8 | 1 | 1 | 1 | 1 |
| 20 | 1 | 1 | 3 | 1 |
| 30 | 2 | 1 + urinal | 4 | 2 |
| 50 | 3 | 2 + 2 urinals | 7 | 3 |
| 100 | 5 | 3 + 3 urinals | 13 | 5 |
The Cal/OSHA column assumes an all-male or all-gender count. If your crew includes women, Cal/OSHA counts each sex separately, which can add a unit. I go deeper on the rules in OSHA porta potty requirements for construction sites.
Construction rentals are billed every 28 days and include weekly service. See our construction porta potty rentals page for how we set up job sites.
How many ADA porta potties do I need?
At an event, at least 5% of the units in each group must be accessible, and that means at least one. Units used only by construction crews are exempt.
The rule comes from the U.S. Access Board’s guide to the 2010 ADA Standards. Where portable units are clustered together, 5% of each cluster has to be accessible, rounded up. Two separate groups of units, say one by the stage and one by the food area, each need their own ADA restroom. The accessible unit also needs a firm, level route to its door. I cover placement in our upcoming post on ADA porta potty requirements.
How many hand wash stations do I need?
On a California job site, one washing station per 20 employees. For events, plan on about one hand wash station for every four units, and more near food.
Cal/OSHA Section 1527 also says the station has to be placed so anyone using a toilet can readily wash, with soap and single-use towels. When the toilets are non-flushing, the washing station must be outside the toilet and not attached to it, except when there are fewer than five employees and only one toilet. Our hand wash station is freestanding with a sink on each side. More on choosing them in the upcoming hand wash station rental guide.
What changes the number of porta potties I need?
Length, alcohol and food push the count up the most. Use this checklist before you call:
- Peak crowd, not total tickets. Count the most people on site at the same time.
- Event length. Longer events mean more uses per unit before it can be serviced.
- Alcohol and drinks. Beer and wine mean more trips. Add about 20%.
- Mostly women guests. If most of the crowd is women, add about 20% more.
- Food. Add hand wash stations next to the food line.
- Layout. If guests are spread across a large site, put units in more than one spot. Each group needs its own ADA unit.
- Who is attending. If you expect lines, a few extra units or a deluxe flushing unit help.
- Servicing. For multi-day events, servicing between days can replace extra units. Event rentals are a flat rate for up to a week, and servicing is added on top.
When should I book, and where do the units go?
Reserve event units at least a week ahead. Deliveries run 7 AM to 4 PM, Monday through Friday, and we need at least two business days of lead time.
Units go on a level spot within 25 feet of the street so our truck can reach them. We do not place units in backyards. Since we deliver on weekdays, a weekend event means a weekday drop-off. We serve the Bay Area, including Oakland, San Jose and Walnut Creek. You can see every unit we rent on our products page, including the standard restroom our calculator counts.
Frequently asked questions
How many porta potties do I need for 100 guests?
For a 100-guest event of up to four hours, plan on two units, one of them ADA. If alcohol is served or the event runs six hours or more, plan on three or four.
How many porta potties do I need for a wedding?
Use the event numbers above. Weddings often run six hours or more with drinks, so most land in the 6 to 8 hour column with alcohol. Many couples add a deluxe unit or a restroom trailer for guests in formal clothes.
Does a small construction crew need its own porta potty?
Yes, unless the crew is a mobile crew with transportation readily available to a nearby toilet. Cal/OSHA requires at least one toilet on a site, and a crew of fewer than five can share one all-gender unit.
Do I have to rent an ADA unit for a private party?
The ADA scoping rules are written for facilities and events open to the public. They may not apply to a private party at your home, but if any guest uses a wheelchair or walker, rent one. Check your permit and venue rules too.
Is one hand wash station enough?
For a small event with one or two units, usually yes. On a California job site, you need one per 20 employees. If food is being served, add one near the food line.
Ready to book? Send us your date, address and head count through our quote form and we will confirm the setup.