A porta potty holds waste in a sealed 60 to 70 gallon tank below the seat, mixed with a blue deodorizing chemical that breaks down solids and cuts odor. No water, no plumbing. A service truck pumps the tank on a route and swaps in fresh chemical, typically once a week under the ANSI/PSAI Z4.3 baseline.
Underneath the seat sits a holding tank, usually 60 to 70 gallons on a standard unit, built into a shell that runs about 44 by 48 inches on the ground and stands close to 92 inches tall. There's no water line and no drain. Waste drops straight into the tank, where blue deodorizing chemical goes to work breaking down solids and locking down smell between service visits. That's the whole system, and it's why these units can sit on a gravel lot in Round Rock or a construction site off I-35 without hookups. A construction worker walking off a slab crew doesn't think about any of this, he just needs the door to open. Vent stacks built into the roof pull odor up and out instead of back into the stall. When a service truck comes through, a tech vacuums the tank empty, rinses it, and refills the chemical charge before locking the unit back up. Compare that to a deluxe flushable porta potty, which adds a small onboard freshwater tank and a foot pump or hand pump to flush, which is closer to what people expect from a restroom trailer than a basic unit. If you're trying to figure out unit counts for a jobsite, the guide on how many porta potties you need walks through OSHA's ratio directly.
A portable sink runs on the same no-plumbing logic as the toilet: a fresh water tank up top, gravity or a foot pump to push it through the faucet, and a gray water tank underneath to catch runoff. Nothing connects to a building. That matters under 29 CFR 1910.141(d)(2), which requires soap and towels or a hand-drying device at washing facilities, since hand sanitizer alone doesn't satisfy it. A handwashing station or portable sink rental pairs naturally with any restroom setup, and on food service or agricultural sites it's often required rather than optional. If your crew is spraying paint, coatings, herbicides or insecticides, OSHA 1926.51(f)(1) kicks in specifically for those contaminant contexts, and a sink has to be close enough to actually get used. We deliver these across Round Rock and out to job sites in Hutto, 8.1 miles east, and Brushy Creek, 6.9 miles west, alongside toilet drops so crews aren't waiting on two separate trucks.
Flushable units carry their own onboard water supply, so pressing the flush pumps a small rinse into the bowl and down into the holding tank below, same tank concept as a standard unit, just with the flush step added. It's not a sewer connection, it's a closed loop between the two tanks. A camping porta potty works the same way; the point is self-contained sanitation with no water or power source nearby, which is exactly the situation at a campsite or a remote lot. For events with higher traffic, a restroom trailer or an 8 stall restroom trailer scales the same idea up with multiple stalls and a bigger holding capacity, and something like a 2 stall restroom trailer works well for a backyard wedding. Whatever the unit, ADA-accessible stalls need to meet ADA Standards section 404.2.3, a 32 inch clear door opening, and ADA Standards section 304.3.1 calls for a 60 inch turning circle inside. When units are clustered for an event, ADA Standards section 213.2 requires at least 5 percent of them to be accessible, never fewer than one.
The blue liquid in a standard unit is a deodorizing and waste-breakdown chemical, refreshed at every service stop, distinct from the enzyme treatments used in septic tank cleaning or the additives some people search for as septic tank cleaning chemicals for a home system. A residential septic tank typically needs pumping every 3 to 5 years depending on tank size and household size, which is a different service entirely from a rental unit's weekly route; our septic pumping service covers both. On a construction jobsite, unit counts follow OSHA 1926.51(c)(1): one toilet for 20 workers or fewer, then one toilet and one urinal per 40 workers up to 200, and one per 50 beyond that. General industry sites in Round Rock instead fall under OSHA 1910.141(c)(1)(i). Ag operations follow OSHA 1928.110, which sets one facility per 20 hand-labor employees within a quarter mile walk. Roll-off delivery for a dumpster or storage container dropped alongside your units needs about 60 feet of straight clearance behind the truck.
| unit | day | week | month |
|---|---|---|---|
| standard | $100-$350 | $130-$500 | $125-$325 |
| ada | $200-$400 | $240-$400 | - |
| deluxe | $85-$1200 | $150-$290 | - |
Weekend rentals for a standard unit run separately from these day and week rates; a wedding or festival booking in Wells Branch, 9.2 miles south, would fall into that weekend band. See full porta potty rental cost breakdowns or the monthly porta potty rental page if you're planning a longer job.
Service trucks pump and restock units on a route, with once a week the baseline for up to 10 users over a 40 hour week under ANSI/PSAI Z4.3. High-traffic events or larger crews need more frequent visits; ask about your specific schedule when you request a quote.
Some odor is normal, especially in heat, but a fresh chemical charge and a working vent stack keep it manageable. Smell usually means a unit is overdue for service or overloaded for its user count. See do porta potties smell for more.
Yes, the liquid chemical can freeze in hard cold, which slows breakdown and can crack components. We adjust chemical mix and service frequency for winter jobs. Details are on the porta potty in winter page.
On stable, level ground with clear access for the service truck, away from doorways and food areas. Our porta potty placement guide covers ground surface and clearance in more depth.
Placement in the public right of way needs confirming with the city before delivery. We check this with you during scheduling rather than guessing; see porta potty permit requirements for what to gather first.
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