Free Tool
Porta Potty Calculator
How many units your crew legally needs, and how many they actually need for a site that doesn’t grind to a halt at 10am — both, sourced and separated so you know which is which.
1. Workers on site per day
2. Project length
OSHA Minimum vs. Industry Best Practice: What’s the Difference?
OSHA Legal Minimum (29 CFR 1926.51)
1 toilet for 20 or fewer workers. For 20–199 workers, 1 toilet and 1 urinal per 40 workers. For 200+ workers, 1 per 50. This is the legal floor — it’s not designed around comfort or line length, just the minimum that keeps you compliant.
Industry Best Practice (ANSI/PSAI Z4.3)
The Portable Sanitation Association International’s standard recommends roughly 1 unit per 10 workers for a standard 40-hour week with weekly servicing. This is what actually keeps a crew productive instead of standing in line — more units and/or more frequent servicing above this line if you’re running multiple shifts or extended hours.
Meeting the OSHA minimum keeps you legal. It doesn’t mean your crew has enough units — most GCs we work with build to the industry recommendation, not the legal floor.
Frequently Asked Questions
Is the OSHA minimum actually enough for my crew?
Legally, yes. Practically, it’s often tight — the OSHA ratio was set as a compliance floor, not a productivity target. Most contractors size to the industry-recommended ratio (about 1 per 10 workers) instead.
Do I need an ADA-accessible unit?
Most active job sites include at least one ADA-compliant unit as standard practice, and some project specs or permits require it explicitly. Check your project requirements, or ask us and we’ll include one by default.
How often do units need to be serviced?
Weekly is standard for typical crew sizes. Larger crews, multiple shifts, or extended hours usually call for twice-weekly service to keep units from filling before the next scheduled cleaning.
What if my crew size changes throughout the project?
Common on longer builds. Call us when your crew size shifts significantly and we’ll adjust unit count or servicing frequency — no need to commit to one number for the whole project.
Is this calculator accurate for special events?
Not directly — event math depends on attendance, event duration, and whether alcohol is served, which follows different guidance than job-site crew ratios. Call us with your event details and we’ll size it properly.
Need units on-site fast? Same-day delivery available in Austin, Denver & San Antonio.
Call (512) 823-1352