How Many Porta Potties Do I Need?

This page is general planning information. Your event permit, your venue's conditions of approval or your safety consultant may set a different number, and that number controls.

What is the standard chart for event porta potties?

The chart most rental companies and several health departments use comes from the Portable Sanitation Association International (PSAI). It gives the number of portable toilets by average crowd size and average hours at the event (PSAI brochure, PDF).

PSAI describes the chart as "a guide when no pumping service is provided, and based on a 50/50 mix of men and women." The brochure credits an independent study by the Center of Business and Industrial Studies at the University of Missouri-St. Louis. Three things follow from those assumptions:

• No existing restrooms are counted. If the venue has working restrooms guests can use, you can order fewer units.
• No pumping during the event. A multi-day event needs the units serviced between days, or more units.
• An even mix of men and women. PSAI says more units are needed when the crowd has a high share of women, in hot weather, and when people are eating and drinking heavily.

San Bernardino County Environmental Health Services publishes the same numbers and extends them to 9 and 10 hours (San Bernardino County, PDF):

Neither chart has a row below 500 people. For smaller gatherings the calculator scales the 500 row down in proportion and never returns fewer than one unit. That scaling is our method, not PSAI's.

We did not find a binding toilets-per-guest ratio in California state law or from Riverside County Environmental Health. The numbers on this page are guidance, and a city's event application can ask for something different.

How much should I add if alcohol is served?

The published sources disagree, so we show each one instead of picking a single figure.

San Bernardino County is next door to Riverside County, not the authority for it. We quote it because it is the nearest health department we found that prints a number.

In the Temecula Valley, alcohol is the normal case. A winery wedding, a brewery anniversary or a festival with a beer garden should start from the PSAI 20% figure, and move toward 40% when drinking is the main activity and guests stay for hours.

How is the FEMA method different?

FEMA's Special Events Contingency Planning manual gives tables for use "where local laws or regulations do not exist." It counts toilets, urinals and sinks separately for men and women, so its totals cannot be laid alongside the PSAI chart as a single range. The link above is a copy of the FEMA pages hosted by the Montana health department. We could not find a current copy on fema.gov.

FEMA then reduces the table by event length: 100% for more than 8 hours, 80% for 6 to 8 hours, 75% for 4 to 6 hours and 70% for less than 4 hours.

The FEMA numbers run far higher than PSAI. For fewer than 500 people with alcohol, FEMA lists 24 toilets and urinals before the duration reduction, where the PSAI chart gives 5 units for 500 people over 4 hours. Use FEMA as the cautious upper reference when a permit reviewer or insurer asks for it. The calculator on this page does not use it.

How many accessible units do I need?

For an event open to the public in California, plan on at least one accessible unit in every group of portable toilets.

• California Building Code. Section 11B-213.2 says that where single-user portable units are clustered at one location, "5 percent, but no fewer than one" of the units at each cluster must be accessible, and those units must carry the International Symbol of Accessibility (2025 CBC text in the Division of the State Architect's advisory manual, PDF).
• Federal ADA Standards. The federal wording is a ceiling: "no more than 5 percent" of the units in each cluster are required to be accessible (U.S. Access Board). California's "no fewer than one" is the stricter rule here.
• City forms can ask for more. Murrieta's and Lake Elsinore's event applications ask for 10% accessible units. Murrieta's adds that a unit placed on its own must be accessible. See the permit guide for links to each form.
• Construction sites are treated differently. Units used only by construction workers are exempt under the federal standards. The Cal/OSHA guide explains the limits of that exemption.

The rule applies per cluster. Twelve units in three groups of four need three accessible units, one in each group. An accessible unit also has to be reachable: level, firm ground and a path a wheelchair can use. More on the unit itself is on our ADA-accessible units page.

How many hand-wash stations do I need?

Job sites. Cal/OSHA sets the number: one washing station for every 20 employees or fraction of 20, and with a portable toilet the station must be outside the unit and not attached to it (8 CCR §1527).

Events. We did not find a published ratio of hand-wash stations to guests for California events. Two points do have sources:

• Riverside County Environmental Health's checklist for temporary food booths calls for restrooms with hand washing within 200 feet of the booths (Riverside County DEH checklist, PDF).
• FEMA's guidance says toilets should be near hand-washing stations, and its tables include sinks.

Our working practice is one hand-wash station at each group of toilets, and more wherever food is served or animals are handled. The calculator returns one station per group as a starting point and labels it a suggestion.

How many portable toilets does a construction site need?

California counts by workers, not hours. The Cal/OSHA construction rules require one toilet for each 20 employees or fraction of 20 (8 CCR §1526) and one washing station on the same ratio (8 CCR §1527).

The toilet column assumes every unit is a single-user unit marked for all-gender use, which is how the rule lets a mixed crew share one count. If units are assigned by sex, each sex is counted separately and the total can rise. The rule does not apply to mobile crews with transportation readily available to nearby toilets. The Cal/OSHA porta potty guide covers the wording, the exceptions and the comparison with federal OSHA.

Count everyone on site, including subcontractors' crews, on the busiest day. Neither rule sets a pumping interval. They require the units to be kept clean and stocked, so a crew near the top of a bracket, or working long shifts in summer, may need a second weekly visit or an extra unit.

What about vineyard and field crews?

Hand-labor agricultural work, including vineyard pruning and harvest, falls under the field sanitation rule, 8 CCR §3457. The numbers match construction: toilets for each 20 employees or fraction, and one hand-washing facility for each 20 or fraction. Two things differ:

• Distance. Facilities must be "within a one-quarter (1/4) mile walk or within five (5) minutes, whichever is shorter." On a large block that can mean more units than the head count alone, or units on a trailer that moves with the crew.
• Records. Written service and maintenance records must be kept for two years.

A crew of fewer than five needs one single-user all-gender unit. The rule also lets the employer provide transportation to facilities instead in limited cases, such as field work lasting under two hours including travel. Section 3457 covers field crews only. Tasting-room and wedding guests are not employees.

Worked examples

A 150-guest winery wedding, 5 hours, wine and beer served

1. The chart starts at 500 guests. Scaling the 500-guest, 5-hour figure (6 units) to 150 guests gives 1.8, rounded up to 2.
2. Alcohol: PSAI's 20% on 2 units gives 2.4, rounded up to 3. San Bernardino County's 40% gives 2.8, also 3.
3. One of the three should be an accessible unit.
4. Hand washing: one or two stations.

Result: 3 units, one of them accessible, and 1 to 2 hand-wash stations. Treat that as the floor. Wedding guides use fuller rules of thumb, such as The Knot's one stall per 25 guests, which would be 6 here (The Knot). Weddings also bunch restroom trips into a few breaks, right after the ceremony and before dinner, so many couples order one or two more than the chart or choose a trailer. See porta potty vs restroom trailer. If the venue's own restrooms will be open to your guests, count them first.

A 1,000-person community festival, 6 hours, with a beer garden

1. Chart: 1,000 people for 6 hours is 9 units.
2. Alcohol: 10% gives 10, 20% gives 11, 40% gives 13.
3. Accessible units: with three groups of toilets, three accessible units, one per group. That also meets the 10% some city forms ask for.
4. Hand washing: one station per group, plus stations at the food area.

Result: 11 to 13 units in total, 3 of them accessible, and at least 3 hand-wash stations. For comparison, Murrieta's application prints a ratio of 1 per 500, which would be 2 units, and FEMA's under-1,000 table with alcohol lists 31 toilets and urinals before its 80% reduction for a 6 to 8 hour event. The city figure is the minimum on a form, the FEMA figure is the cautious extreme, and the chart sits between them.

A 12-person framing crew on a custom home

Twelve workers is one bracket of 20. Result: 1 portable toilet and 1 hand-wash station. Because there are five or more workers, the station has to be outside the unit. One weekly service is the usual starting point.

A 45-person commercial site

Forty-five is two full brackets of 20 plus a fraction. Result: 3 portable toilets and 3 hand-wash stations, with the units marked all-gender. If the site assigns units by sex instead, count each separately: 38 men and 7 women is 2 plus 1, still 3, but 41 men and 4 women is 3 plus 1, which is 4. A site this size often spreads units across floors or work areas, and pricing for multiple units is on our pricing page.

Frequently asked questions

How many porta potties do I need for 100 guests? Scaled from the chart, one unit covers 100 guests for up to 4 hours and two units cover 5 to 8 hours. With alcohol, order two even for a short event. If the event is open to the public, one unit must be accessible.

Do the venue's restrooms count? Yes. The chart assumes no fixed restrooms. Subtract what the venue has, but check that those restrooms will be unlocked and that any septic system can take the load.

Does the chart work for a multi-day event? Only if the units are pumped between days. The chart assumes no service during the event. FEMA's guidance calls for service on a 24-hour schedule, and Murrieta's event form requires daily service on multi-day events.

Is one porta potty enough for a home remodel? For a crew of up to 20, one unit meets the Cal/OSHA count. Crews of five or more also need a hand-wash station outside the unit.

Should I round up or down? Up. Every source on this page rounds a fraction to the next whole unit, and a line at the restrooms is what guests remember.

Can you tell me the number for my permit application? Yes. Tell us the attendance, hours, alcohol service and the city, and we will give you a count and the unit types to write on the form.

Get a count and a price

Call (951) 517-3600 between 7 a.m. and 7 p.m., any day of the week, or send the form with your head count, hours and location. Victory Portable Restrooms delivers standard units, accessible units and hand-wash stations from our Murrieta yard across the Temecula Valley and western Riverside County.