· Reviewed against source documents August 2026
OSHA portable toilet requirements for construction sites
OSHA 29 CFR 1926.51(c) requires employers to provide adequate and readily accessible toilet facilities at every construction work location, with the minimum unit count set by the number of workers on site at any one time.
| Number of workers on site | Minimum facilities required |
|---|---|
| 20 or fewer | 1 toilet |
| 21 to 199 | 1 toilet seat and 1 urinal per 40 workers |
| 200 or more | 1 toilet seat and 1 urinal per 50 workers |
Source: U.S. Occupational Safety and Health Administration, 29 CFR 1926.51(c). View the primary source. Verified August 2026.
How many portable toilets does OSHA require on a construction site?
OSHA 29 CFR 1926.51(c)(1) sets three tiers: 1 toilet for 20 or fewer workers, 1 toilet seat and 1 urinal per 40 workers from 21 to 199 workers, and 1 toilet seat and 1 urinal per 50 workers at 200 or more.
The figure that matters is peak simultaneous headcount, not the total roster on the project. A job with 60 tradespeople on the books but never more than 25 on site at once is sized against 25, not 60. Superintendents who size against the roster consistently over-order, and those who size against an average day under-order on the weeks that matter.
Does a dirty unit still count toward the OSHA minimum?
No. A portable toilet only counts toward the required minimum if it is clean and in working order.
This is the part of the standard that turns a purchasing decision into a scheduling decision. A 60 to 70 gallon holding tank serves roughly a 10-person crew for one week. If you place one unit for a 20-person crew because that is the OSHA line, that unit reaches capacity in roughly half a week, and for the back half of the week you are not compliant even though the required unit is physically present. Sites running near the minimum need twice-weekly service to stay inside the standard.
Are handwashing facilities required on Wisconsin construction sites?
Yes. OSHA requires handwashing facilities alongside toilet facilities on construction sites.
The common Wisconsin practice is one portable hand-wash station for every two portable toilets. Between roughly December and March that pairing breaks down, because a hand-wash station holds untreatable fresh water that will freeze. Most Wisconsin sites pull sinks for the winter and substitute hand sanitizer dispensers mounted inside the units, then bring sinks back once overnight lows clear freezing.
Is the construction standard different from the general industry standard?
Yes. Construction sites fall under 29 CFR 1926.51, while fixed workplaces fall under the general industry sanitation standard at 29 CFR 1910.141, and the two use different tables.
Applying the general industry table to a construction site, or the reverse, is one of the more common compliance errors we see. If your site is active construction, alteration, or repair work, 1926.51 governs.
What does OSHA compliance cost on a Wisconsin job site?
Budget $150 to $275 per unit per month with weekly service, rising to $195 to $340 per unit per month once winter antifreeze charging starts in December.
Twice-weekly service, which sites at the OSHA minimum effectively require, runs $240 to $425 per unit per month. Hand-wash stations add $110 to $200 per station per month. Those are Wisconsin market ranges observed in 2026 and include delivery, scheduled servicing, and pickup.
Key points
- The count is based on the maximum number of workers on site at any one time, not the total project roster across the whole build.
- A unit only counts toward the required minimum if it is clean and in working order. A soiled or out-of-service unit does not satisfy the standard.
- Handwashing facilities are required alongside toilet facilities.
- The construction standard at 29 CFR 1926.51 is separate from the general-industry sanitation standard at 29 CFR 1910.141, which applies to fixed workplaces and uses a different table.
Frequently asked
How many porta potties do I need for 10 workers?
One unit satisfies OSHA 29 CFR 1926.51(c) for any crew of 20 or fewer. At 10 workers a single unit with standard weekly service is also a realistic match for tank capacity, since a 60 to 70 gallon tank serves about a 10-person crew for one week.
How many porta potties do I need for 50 workers?
At 50 workers OSHA requires 1 toilet seat and 1 urinal per 40 workers, which puts the requirement at 2 toilet seats and 2 urinals. On tank capacity alone, 50 workers will fill roughly five 10-person unit-weeks, so most Wisconsin contractors run 3 to 5 units with weekly service rather than 2 units serviced constantly.
Who is responsible for providing toilets on a multi-employer construction site?
OSHA places the duty on the employer to provide adequate and readily accessible facilities at every work location. On multi-employer sites the general contractor typically supplies site-wide facilities under the prime contract, but each employer remains responsible for its own workers having access.
Does OSHA require a separate toilet for women on a construction site?
29 CFR 1926.51 does not mandate separate facilities by sex on construction sites the way the general industry standard does for fixed workplaces. Single-occupancy portable units satisfy the construction standard, though many Wisconsin general contractors designate units voluntarily.
Need this applied to your specific site? One call.
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