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OSHA Porta Potty Calculator — How Many Units Do You Need?

Size your porta potty rental in 30 seconds. Pick construction or event mode below — we apply OSHA 29 CFR 1926.51 ratios for job sites and industry sizing rules for events, including ADA and hand-wash recommendations.

OSHA sizes by your peak (largest concurrent) crew, not total headcount.

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    How the calculator sizes your rental

    Construction (OSHA 29 CFR 1926.51)

    • ≤ 20 workers: 1 toilet
    • 21–199 workers: 1 toilet seat + 1 urinal per 40 workers (rounded up)
    • 200+ workers: 1 toilet seat + 1 urinal per 50 workers
    • Hand-wash: Required when workers consume food on site (OSHA 1926.51(f))

    Events (industry standard)

    • Baseline: 1 unit per 50 guests for a 4-hour event
    • Longer events: Scale linearly by hours / 4
    • Alcohol: Add 50% to total unit count
    • ADA: At least 1 ADA-accessible unit per event

    These ratios are conservative — they're the minimums OSHA enforces and the planning numbers professional event planners use. Actual unit count for your project may be higher if you have unusual peak load (lunch breaks, intermissions, late-day arrivals). When in doubt, call us — we size hundreds of Tulsa projects a year and will give you a straight answer over the phone.

    FAQ

    How many porta potties does OSHA require for a construction site?
    OSHA 29 CFR 1926.51(c)(1) requires 1 toilet for crews of 20 or fewer workers, 1 toilet seat + 1 urinal per 40 workers for 20–199, and 1 toilet seat + 1 urinal per 50 workers for 200+. Use the calculator above to size your specific crew.
    How many porta potties do I need for an event?
    Industry rule of thumb: 1 unit per 50 guests for a 4-hour event. Scale up by 50% if alcohol is served, and proportionally for longer events. The calculator handles this automatically when you switch to event mode.
    Does OSHA require hand-washing stations?
    Yes — OSHA 29 CFR 1926.51(f) requires hand-washing facilities at any construction site where food is consumed. The calculator recommends 1 hand-wash station per 4 toilet units when food consumption is indicated.
    How many ADA porta potties do I need?
    ADA Title III recommends at least 1 ADA-accessible unit per event, plus 5%–10% of total units (1 per 10 standard units is a common planning ratio). For construction sites, ADA units are required when any worker requests one as a reasonable accommodation.
    Can I just call instead of using the calculator?
    Of course — call (833) 652-9344 and we'll size it for your Tulsa project or event. Most quotes take under 5 minutes over the phone. The calculator is here for planning before you commit to a timeline.

    Skip the math — call Tulsa's local team

    We'll size, schedule, and quote your rental in under 5 minutes.

    (833) 652-9344

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    (833) 652-9344
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