How many porta potties does OSHA require on a job site?
OSHA 1926.51(c) sets a bracket table, not a guess. For 20 workers or fewer, you need 1 toilet facility. From 20 up to 40 workers, that becomes 1 toilet seat and 1 urinal. At 200 or more workers, it steps down to a ratio of 1 seat and 1 urinal per 50 workers. A framing crew of 15 on a residential job in Olympia needs just one standard porta potty rental. A commercial build with 60 tradespeople on site needs to run the math against the 40-worker bracket, and most contractors round up rather than land right on the line. If your crew works with paints, coatings or solvents, OSHA 1926.51(f)(1) adds a washing requirement for that contamination, separate from the toilet count. For a full breakdown by crew size, see our OSHA portable toilet requirements page, and check porta potty rental cost before you commit to a headcount.
How many portable toilets do I need for an event?
Start at 1 unit per 50 guests for a standard 4 hour event with no alcohol. Push that to 1 per 35 to 40 guests if beer or wine is being served, since alcohol increases both frequency of use and bathroom line length fast. A 150-person backyard wedding in Olympia running 5 hours might need 3 to 4 standard units, while the same guest count with an open bar and a 7 hour reception should plan for 5. Multi-day festivals compound the math further: each added day means more waste volume per unit, not just more hours of use. For weddings specifically, our wedding restroom rental guide walks through the guest-to-unit ratio with alcohol built in, and festival restroom rental covers multi-day math for county fair-scale crowds. If the event includes a step or slope to the units, ADA Standards section 405.2 caps ramp slope at 1:12, worth checking before you finalize the site layout.
Should I add an ADA-accessible unit?
Yes, if you are clustering standard units at all. ADA Standards section 213.2 requires that when portable toilets are grouped together, at least 5 percent of the cluster be accessible, and never fewer than one unit even if the cluster is small. That means a 20-unit event lineup needs at least one ADA accessible porta potty, and a 3-unit backyard party still needs one. The accessible unit needs a 60 inch turning circle inside per ADA Standards section 304.3.1, and the door opening has to clear 32 inches per ADA Standards section 404.2.3. Ground leading up to it needs to be stable and slip resistant under ADA Standards section 302.1, which matters on a gravel lot or unfinished pad. Budget separately for it: ADA units run their own price band, distinct from standard porta potty rental pricing, and swapping one standard slot for an ADA slot in your count is the easiest way to stay compliant without overbuilding.
What is the worked example for a construction site?
Take a 35-person crew building a strip mall outside Olympia. That crew sits in the 20-to-40 bracket under OSHA 1926.51(c), which calls for 1 toilet seat and 1 urinal. Most contractors translate that into 2 units on site, often one standard and one deluxe if the foreman wants a flushable option for supervisors. Add a handwashing station regardless of crew size, since OSHA 1926.51(a)(1) requires an adequate supply of potable water at every job site, and 29 CFR 1910.141(d)(2) requires soap and towels or a hand-drying device at any washing facility, not sanitizer alone. If the crew is spraying coatings or using solvents, OSHA 1926.51(f)(1) kicks in and you will want a dedicated washing setup near that work. A handwashing station rental alongside your toilets covers both the water supply rule and the soap-and-towel rule in one placement, and pairing it with a construction dumpster rental keeps the whole site compliant in one delivery.
How many porta potties for a wedding or event with alcohol?
Bump your baseline ratio down from 1-per-50 to 1-per-35 or 1-per-40 once alcohol is in play. A 200-guest wedding at a venue near Olympia with a 6 hour open bar reception should plan for roughly 5 to 6 units, split between standard porta potty rental and at least one deluxe flushable porta potty near the seating area. Guests drinking for several hours use the restroom more often and stay longer per visit, which is why the ratio tightens instead of holding steady. Multi-day events, like a 3-day outdoor festival, need units serviced more than once under the ANSI/PSAI Z4.3 baseline interval, which sets one service visit per week for up to 10 users over a 40 hour week as the standard cadence; a busy festival weekend blows past that fast and needs extra service stops. Check event restroom rental for a fuller ratio table by guest count and hours.
How much dumpster capacity do I need alongside my toilets?
If you are running toilets on a construction site, you are probably also hauling debris, and dumpster size follows job scope the same way toilet count follows crew size. Wondering how many cubic feet in a 10 yard dumpster: it holds about 10 cubic yards, which works out to roughly 270 cubic feet, right for a single-room renovation. How many cubic feet in a 20 yard dumpster and how many tons does a 20 yard dumpster hold: it holds close to 540 cubic feet and typically 2 to 3 tons of debris, sized for a roof tear-off or a small addition. How many feet is a 20 yard dumpster: the container itself runs about 22 feet long, with a 10 yard unit closer to 14 feet. How many tons does a 30 yard dumpster hold: a 30 yard box runs about 810 cubic feet and can carry up to roughly 3 to 4 tons depending on material density, common for a full home renovation. How many tons does a 40 yard dumpster hold: a 40 yard dumpster tops out near 1,080 cubic feet and 4 to 5 tons, sized for new construction or a large commercial cleanout. Check dumpster sizes and dimensions for exact measurements by size, and remember a roll-off delivery needs about 60 feet of straight clearance behind the truck to drop the container safely.
Where should I place units on a tight Olympia lot?
Placement drives count almost as much as headcount does. If your lot is narrow, spreading 4 units across two clusters instead of one line can cut wait times without adding a single unit. Keep the accessible route to any ADA unit at least 36 inches wide under ADA Standards section 403.5.1, and make sure operable door hardware needs no more than 5 pounds of force and no tight grasping, per ADA Standards section 309.4, since a stiff door latch defeats the accessible unit even if everything else is right. On sites near Tumwater or Tanglewilde where the ground is soft after rain, ask about pad placement before delivery rather than after. Our porta potty placement guide covers ground clearance and access lane width in more detail, and if you are not sure whether your setup needs a right-of-way check, placement in a public street or sidewalk area needs confirming with the City of Olympia before delivery.
How many porta potties do I need for 100 guests?
Plan for 2 units minimum at a 1-per-50 ratio for a standard 4 hour event with no alcohol. Push to 3 units if you are serving beer or wine, since the tighter 1-per-35 ratio applies once alcohol enters the picture. Add an ADA unit if you are clustering more than one standard unit together.
How many porta potties do I need for a construction crew of 10?
One toilet facility covers a crew of 10 under OSHA 1926.51(c), which sets the threshold at 20 workers or fewer for a single unit. Most contractors still add a handwashing station separately, since the toilet count and the water-supply requirement under OSHA 1926.51(a)(1) are two different rules.
Do I need an accessible unit for a small event?
Yes. ADA Standards section 213.2 requires at least one accessible unit whenever portable toilets are clustered, with no exception for small groups. Even a 3-unit lineup at a backyard party in Olympia needs one ADA-compliant unit in that cluster.
How often do event porta potties need servicing?
The ANSI/PSAI Z4.3 baseline sets one service visit per week for up to 10 users across a 40 hour week. A high-traffic weekend event with alcohol and heavy use needs servicing more than once during the event, not just before and after.
What is the difference between crew size and guest count for toilet math?
Crew size follows OSHA 1926.51(c) bracket ranges built around 8 to 10 hour work shifts. Guest count follows a per-50 or per-35 ratio built around a single 4 to 6 hour event window, which is why a 40-person office and a 40-guest party need different unit counts.
Can I mix standard and deluxe units in the same count?
Yes, and many Olympia events do. A common setup pairs standard porta potty rental units for general guest use with one deluxe flushable porta potty near the head table or VIP area, counting both toward your total ratio.
Next step
Get a delivery date
Tell us the address, the dates and the headcount. We size the order and confirm the route.