Sizing guide + calculator
How Many Porta Potties Do I Need?
Plan 1 porta potty per 50 guests for a 4-hour event, add half again for longer events and 1 more for alcohol. Job sites need 1 toilet per 20 workers. Use the calculator, then check the legal minimums below.
- Routes we drive:
- Hwy 1
- Hwy 20
- US-101
- Hwy 128
Porta potty calculator
Enter your guest count, event length and whether alcohol is served. The calculator shows the units Terra Porta Rentals recommends, how many must be wheelchair-accessible, and the Mendocino County minimum. Add a crew size to see the Cal/OSHA job-site count. Every step of the math is shown.
How many porta potties per guest do I need?
The event number starts with guests divided by 50, rounded up. For events longer than 4 hours, add half that number again, rounded up. If alcohol is served, add 1 more. At least 5% of the units, and never fewer than one, should be wheelchair-accessible under the 2010 ADA Standards.
- Example: 230 guests ÷ 50 = 4.6 → 5 units.
- The wedding runs 7 hours, so add half of 5 = 2.5 → 3 more (8 total).
- There is a bar → add 1 (9 total).
- 5% of 9 is 0.45, so 1 of the 9 is wheelchair-accessible.
This is Terra Porta Rentals' planning rule, built for short lines at peak times. It is above the legal minimum. Federal accessibility rule: 2010 ADA Standards §213.2.
What are the legal minimums in Mendocino County?
Mendocino County community events with food need at least 1 toilet and 1 handwashing facility per 100 patrons. California construction sites need 1 toilet per 20 employees. California farm crews need 1 toilet and 1 handwashing facility per 20 employees within a quarter-mile walk. Our recommendation sits above all three.
| Setting | Legal minimum | Source | Our recommendation |
|---|---|---|---|
| Public event with food | 1 toilet + 1 handwashing per 100 patrons | Mendocino County event application | 1 per 50 guests, + extras above |
| Food booth workers | 1 toilet per 15 workers within 200 ft | Mendocino County event application | Same |
| Construction | 1 toilet per 20 employees | Cal/OSHA 8 CCR 1526 | 1 per 10 with weekly service |
| Farm crews | 1 toilet + 1 handwashing per 20, within ¼ mile | Cal/OSHA 8 CCR 3457 | Same, moved with the crew |
| Accessible units | 5% of each cluster, at least 1 | 2010 ADA Standards §213.2 | Same |
Not legal advice. Confirm with your permit office or venue.
Questions renters ask
How many porta potties do I need for 100 guests?
A 100-guest event up to 4 hours needs 2 standard porta potties. If it runs 5–8 hours, plan 3. With alcohol served over a long evening, plan 4. Make one of them wheelchair-accessible if the event is open to the public.
How many porta potties for a crew of 30?
Cal/OSHA 8 CCR 1526 requires at least 2 toilets for 30 construction workers. With weekly service we recommend 3, or 2 with twice-weekly service. Add a hand wash station for the washing requirement.
Does a restroom trailer count as more than one porta potty?
Terra Porta Rentals counts one two-stall restroom trailer as about 3 standard units for planning. Each stall flushes and refreshes quickly, so lines move faster than at a single porta potty.
Got your number? Book it.
Call with your count and date. We'll double-check it on the phone.
(707) 360-1810 Calls answered daily, 7 am – 7 pm. Online quotes answered within 30 minutes during those hours.