How Many Porta Potties Do I Need?

There is no single federal rule for how many portable restrooms a festival or block party needs, so the industry works from planning guidelines built on crowd size and how long people stay. The common starting point is two units for the first hundred guests at a four-hour event, then more as the hours and the headcount grow. A rough planning table is below; it's a guideline, not a law, and the event's own permit may set a higher number.

Two things push the number up. Alcohol roughly doubles restroom traffic, so plan on about a third more units when you're serving. And an event that runs all day needs either more units or a mid-event service, because a unit that's full at hour five is a unit nobody will use at hour six.

If food is served, put hand wash stations where people eat and near the restrooms. For anything open to the public, the ADA rule below applies too.

Where portable toilets are provided at a single location, the ADA Standards require at least 5 percent of them, and no fewer than one, to be accessible. Each cluster counts on its own, so an event with restrooms at two gates needs an accessible unit at each gate, not one for the whole site. Construction sites are the one place the Standards exempt from this requirement, though an accessible unit is still the right call wherever the public or office staff will use the restrooms.

An accessible unit is wider, has grab bars and a level entry, and takes up more room on a trailer, so tell us up front. On a Philadelphia street festival the accessible units are also the ones the Streets Department will ask about when they review your footprint.

A rowhome gut rehab in Point Breeze with six people on site: one standard unit, serviced weekly, set in the back yard or at the curb cut where the service truck can reach it. If there's no yard and the unit has to go on the sidewalk, that's a conversation with the Streets Department before it's a conversation with us, and the block's neighbors will have opinions about where it goes. One unit covers this crew with room to spare; the only reason to add a second is a crew that swells to a dozen for the drywall week and a client who'd rather not have the trades waiting in line.

A twelve-story residential tower in University City with 60 workers on site at the peak of the concrete and framing schedule: OSHA's table puts you at two toilet seats and two urinals, which two standard units cover. In practice this job needs more than two, because of where the workers are. A crew on the tenth floor is not going to ride the hoist down for a toilet on the ground, and OSHA's rule assumes the toilet is reachable. The usual answer is ground units for the trades at grade, plus high-rise units (narrow enough to go up on the hoist) every few floors, with a holding tank on the floor to pump into. That's a service plan as much as a unit count, and it changes as the floors top out.

A Saturday street festival on Passyunk Avenue, 2,000 people over eight hours, beer garden at one end: the planning table says about 22 units, add a third for alcohol, so plan on 28 to 30, in clusters at both ends and the middle rather than one long row, each cluster with an accessible unit and a hand wash station. A mid-day service visit keeps the count from being higher. The festival's own permit will set the final number, and the accessible units are the first thing the reviewer checks on the site plan.

A hand wash station is a free-standing cabinet with a fresh water tank, a foot pump, soap and paper towels, usually with two sinks, one on each side. It's not a restroom and it doesn't count toward the toilet numbers above, but on two kinds of jobs it's the piece people forget. The first is any site where OSHA's sanitation rule applies and there's no running water: the rule expects hand washing facilities, and a sanitizer dispenser inside the unit is a stopgap, not a sink. Crews working with concrete, paint, coatings, lead-safe renovation or anything else that comes off with soap and water need a sink near the unit.

The second is any event with food. The health permit for a food event will ask about hand washing for the vendors, and the guests expect it too; nobody wants a cheesesteak after a porta potty with no sink. One station for every four to six units is a sensible starting point at an event, placed between the restrooms and the food, where people will actually use it. For a job site, one station per cluster of units is the norm.

Water tanks on a hand wash station run out before the toilet does. On a hot day with a crowd they can need a refill mid-event, which is one more reason to put a service visit in the plan for anything longer than a few hours.

July in Philadelphia changes the arithmetic. People drink more, the tank fills faster, and a unit that sat in full sun all afternoon is a unit nobody will choose to use. Put the units in shade where you can, on the north side of a building or under trees, and plan a second weekly service for a job site crew on a summer schedule. For an event in the heat, a mid-event service is the difference between the restrooms at hour six and a complaint on social media by hour seven.

January brings the opposite problem. A unit on an exposed site in a cold snap can freeze in the tank, and the walk from the fourth floor of a building to a toilet across a windy lot is a walk a crew will put off. Winter is the season to move the ground units closer to the entrance, keep them out of the wind if the lot allows, and talk to us about winter service before the first hard freeze rather than after.

Philadelphia's big outdoor calendar runs from the Broad Street Run in May through the Thanksgiving parade, with block parties, church festivals and the Mummers in between, and the best weekends get booked early. For an event, get your unit count in a month out; for a job site, a week's notice is plenty most of the year.

Every count above assumes the units are serviced on schedule: pumped, cleaned, restocked and sanitized. Weekly service is the standard for a job site. For an event longer than a day, or a job running two shifts, a second weekly service or a mid-event service keeps the count where it is; without it you need more units. Tell us the shifts and the hours and we'll size the service with the units.

If you'd rather not do the math, use the quote form with your headcount or crew size and we'll come back with the number. There's more on job-site units on our Porta Potty Rental in Philadelphia page and on events.