How many porta potties do I need for a jobsite?
OSHA 1926.51(c) sets the baseline: 1 toilet facility for 20 workers or fewer, 1 toilet seat and 1 urinal per 40 workers once you pass 20, and 1 seat and 1 urinal per 50 workers at 200 or more. A 15-person framing crew in Gaithersburg needs exactly one standard porta potty rental. A 60-person crew building out a strip center falls into the 40-to-199 bracket, so you'd need at least two seats and two urinals under that ratio. Most GCs round up rather than split hairs on the math. If your project runs weeks not days, a monthly porta potty rental usually beats booking week to week, and our construction site services page walks through bundling toilets with fencing and a dumpster on one ticket.
How many portable toilets do I need for an event?
Events run on a faster ratio than jobsites because everyone shows up in the same 3 to 4 hour window instead of spreading out over an 8 hour shift. Here's how it breaks down by headcount and duration:
| Guests | 4 hours | 8 hours | Add per extra 4 hrs |
|---|---|---|---|
| 100 | 2 units | 3 units | +1 unit |
| 250 | 4 units | 6 units | +2 units |
| 500 | 8 units | 11 units | +3 units |
| 1000 | 15 units | 20 units | +5 units |
A 250-guest fundraiser running 4 hours needs 4 units minimum, plus one accessible unit per ADA Standards section 213.2, which requires at least one accessible unit in any cluster and never fewer than 5 percent once you scale up. Check our event restroom rental page or the festival restroom rental page if you're planning something bigger than a backyard party.
Does serving alcohol change the count?
Yes, and it's not small. Alcohol adds roughly 30 to 40 percent more toilet demand because people drink more liquid and use the bathroom more often per hour. A 300-guest wedding with an open bar running 6 hours should plan closer to 8 units instead of the 6 a dry event of the same size would need. Add at least one deluxe flushable porta potty near the bar area so the line doesn't back up into the dance floor. Our wedding restroom rental page has more on siting near tents and catering tables. If you're not sure where the units should sit relative to parking and power, the porta potty placement guide covers ground clearance and setback basics.
How many units for a multi-day event?
Multi-day festivals need more units per guest than a single afternoon, because service crews can't turn a unit around as fast when foot traffic never really stops. ANSI/PSAI Z4.3 sets a baseline service interval of once per week for up to 10 users across a standard 40 hour week, which is built for steady jobsite use, not a three-day festival running 12 hours a day. For events like that, we typically service twice daily rather than stretch to the weekly baseline. A 3-day county fair pulling 2,000 people a day in Gaithersburg needs the daily headcount math run fresh for each day, plus a service plan that accounts for overnight security and lighting. Check our county fair restrooms page and consider a light tower rental if the grounds go dark after sunset.
Worked example: 400-person outdoor wedding, 6 hours, open bar
Start with the base ratio for 400 guests over 6 hours, which lands around 9 to 10 standard units. Add the alcohol adjustment, bumping that to roughly 12 to 13 units. Swap 2 of those for ADA accessible porta potty units to satisfy ADA Standards section 213.2, and add one deluxe flushable porta potty near the head table. That puts you at 13 to 14 total units, or you could consolidate into a 4 stall restroom trailer plus 2 standalone units for overflow. A standard unit rents for a weekend in the 125 to 400 dollar range depending on count and add-ons, so pricing out the full mix is worth doing before you commit to a layout. Our restroom trailer rental page breaks down stall counts if a trailer makes more sense than a row of standalone units.
Worked example: 80-worker commercial build, 10 weeks
Eighty workers puts you in the 40-to-199 bracket under OSHA 1926.51(c), meaning at least 2 toilet seats and 2 urinals as a floor, though most supers on an 80-person site order 3 to 4 units to avoid lines at lunch. Add a handwashing station if the crew is doing any painting, coatings or pesticide work, since OSHA 1926.51(f)(1) specifically requires washing facilities for that kind of exposure, not general use. A monthly porta potty rental across 10 weeks runs cheaper per week than renting daily the whole stretch, and pairing it with a 30 yard dumpster rental for framing debris keeps the site clean under OSHA 1926.25 housekeeping rules. A 30 yard dumpster holds roughly 30 cubic yards of debris and typically handles 4 to 6 tons before you hit weight limits, worth checking against our dumpster weight limits page if you're loading heavy material like shingles or concrete.
What if I'm not sure and want to be safe?
Round up, not down. It's cheaper to release a unit early than to have a line form mid-event or a crew standing around waiting for a stall. Gaithersburg sites within a few miles of each other, from Flower Hill at 1.9 miles northeast to Montgomery Village at 3.9 miles north, all face the same permit and placement questions, so ask your provider to walk the site or review a plan before delivery day. If you're renting for a single afternoon, our porta potty rental per day page has current pricing, and the porta potty rental cost page breaks out how delivery and service fees stack on top of the base rate. Placement in the public right of way in Gaithersburg needs confirming with the city; we don't guess at that and neither should you.
How many toilets do I need for 50 guests?
Two units covers a 50-guest event running 4 hours under standard planning ratios. Push to 3 if you're serving alcohol or running past 4 hours. Add an ADA accessible porta potty unit regardless of headcount, since ADA Standards section 213.2 requires at least one in any cluster.
How many cubic feet are in a 10 yard dumpster?
A 10 yard dumpster holds about 270 cubic feet of debris, roughly enough for a single room renovation or a small deck teardown. Check 10 yard dumpster rental for sizing against your specific cleanup job.
How many tons does a 20 yard dumpster hold?
A 20 yard dumpster typically handles 2 to 3 tons before hitting standard weight limits, which comes out to about 540 cubic feet of volume. Heavier material like roofing or concrete fills the weight limit long before the box looks full, so check dumpster weight limits before loading.
How many tons does a 30 yard dumpster hold and how many feet long is it?
A 30 yard dumpster typically holds 4 to 6 tons and measures about 810 cubic feet in volume, usually built on a frame around 22 feet long. See 30 yard dumpster rental for delivery clearance and placement details specific to that size.
How many tons does a 40 yard dumpster hold?
A 40 yard dumpster typically handles 5 to 7 tons and holds roughly 1,080 cubic feet, making it the largest standard roll-off most residential streets can accommodate. Review 40 yard dumpster rental and dumpster sizes and dimensions before ordering for a full teardown or large renovation.
Do I need more units if my event runs past 8 hours?
Yes, add roughly one unit per extra 4 hours beyond your base count once headcount and duration are set. A 500-guest event running 12 hours instead of 8 needs 3 more units than the 8 hour figure. Multi-day events compound this further, so plan service visits accordingly rather than stretching a single delivery across several days.
Next step
Get a delivery date
Tell us the address, the dates and the headcount. We size the order and confirm the route.