Sizing guide

How Many Porta Potties Do You Need?

For a four-hour event, plan one porta potty per 50 to 75 guests, and one per 50 when alcohol is served. For construction, OSHA requires at least one toilet up to 20 workers, with ratios scaling from there. The tables below do the math for you.

Austin Portable Toilets sizes orders like this every day, and the counts below match what we recommend on the phone. When an event has unusual shape to it, long hours, heavy food service, a gated site, call and we will adjust the plan to fit.

Event table: guests to units

Guests	Up to 4 hours	4–8 hours	With alcohol (4 hrs)
50	1	2	2
100	2	3	3
150	3	4	4
250	4	6	5
500	7	10	9
1,000	13	18	16

Two adjustments cover most real events. Alcohol raises restroom traffic by roughly 15 to 20 percent, which is why the bar column runs heavier. And events where guests arrive and leave together, like ceremonies and race starts, need more capacity than the same headcount trickling through a fair.

The ADA count

Public events should make at least 5 percent of units wheelchair accessible, with a minimum of one accessible unit at each restroom cluster, placed on the accessible route. Details on the units themselves are on our accessible unit page. For a typical wedding or party, the practical answer is one ADA unit alongside the standard units.

Job site table: OSHA worker ratios

OSHA's construction sanitation standard, 29 CFR 1926.51, sets minimums by crew size. As of 2026 the ratios read like this in practice:

Workers on site	Minimum required
20 or fewer	1 toilet
21 – 40	1 toilet + 1 urinal
41 – 80	2 toilets + 2 urinals
81 – 120	3 toilets + 3 urinals
Over 200	1 toilet + 1 urinal per 50 workers

Size to the peak week of the schedule, not the average, because the standard applies on the day the inspector visits. Crews that run through an Austin summer are happier at one unit per 10 to 15 workers than at the legal floor, and a wash station beside the units earns its rate on any site with concrete or paint in scope. How the rentals run week to week is covered on the job site rental page.

When the math says trailer

Past a certain guest profile, more standard units stop being the right answer. Weddings, galas, and client-facing corporate events near the 100-guest mark are usually better served by a multi-stall trailer with running water plus a small number of standard units for peak capacity. The count drops and the guest experience climbs at the same time.