For most construction crews, plan on 1 portable toilet per 20 workers on an 8 to 10 hour shift under OSHA 1926.51(c). For events, use 1 unit per 50 guests for a 4 hour event. St. Louis Porta Pros builds both counts out below, with worked examples and a table for each situation.
Start with OSHA 1926.51(c): 1 toilet for 20 or fewer workers, then 1 toilet seat and 1 urinal per 40 workers once you pass 20, and 1 seat plus 1 urinal per 50 workers once the crew hits 200 or more. A 35-person crew working a standard shift needs 2 units under that bracket. A 75-person crew lands in the 40-worker bracket and needs roughly 2 units plus the added urinal capacity. If painters, roofers or anyone applying coatings or insecticides is on site, OSHA 1926.51(f)(1) also requires washing facilities for that work, separate from the toilet count, so pair units with a handwashing station rental. Crews working near St. Louis on multi-week builds usually pick a standard porta potty rental with a 60 to 70 gallon tank rather than swapping units weekly. Check the full bracket table and see how OSHA portable toilet requirements apply to your headcount before you order.
Events run on guest count and hours, not worker headcount, and alcohol changes the math fast. A dry event needs about 1 unit per 50 guests over 4 hours. Add beer or wine service and that ratio tightens to closer to 1 per 35 to 40 guests, since drinking drives more frequent visits. A wedding for 150 guests over 5 hours with a bar typically needs 4 to 5 standard units, or fewer stalls if you upgrade to a restroom trailer rental with multiple stations inside one unit. For anything formal, at least one unit should meet ADA restroom requirements under ADA Standards 213.2, which requires 5 percent of clustered units to be accessible with a minimum of one. Browse event restroom rental options or check wedding restroom rental packages sized for St. Louis venues.
| Workers on site | Toilets required |
|---|---|
| 20 or fewer | 1 |
| 20 to 39 | 1 toilet seat, 1 urinal |
| 40 to 59 | 2 toilet seats, 2 urinals |
| 60 to 79 | 3 toilet seats, 3 urinals |
| 80 to 99 | 4 toilet seats, 4 urinals |
| 200 or more | 1 seat and 1 urinal per 50 workers |
This bracket comes straight from OSHA 1926.51(c) and applies to construction sites, not offices. If your project is a general industry workplace instead of a jobsite, the ratio comes from 1910.141(c)(1)(i) instead, which uses a different bracket. Farms and agricultural operations follow a separate rule, OSHA 1928.110, which calls for one facility per 20 hand-labor employees within a quarter mile walk, relevant for anyone running farm and agricultural restrooms outside the city.
| Guests | Duration | Units (no alcohol) | Units (with alcohol) |
|---|---|---|---|
| 50 | 4 hours | 1 | 2 |
| 100 | 4 hours | 2 | 3 |
| 150 | 5 hours | 3 | 4 to 5 |
| 250 | 6 hours | 5 | 7 |
| 500 | 8 hours | 10 | 13 to 14 |
Multi-day festivals need a service plan on top of the count, not just more units. ANSI/PSAI Z4.3 sets a baseline service interval of once per week for up to 10 users over a 40 hour week, so a three-day festival pulling heavy traffic needs at least one extra service visit scheduled mid-event, not just a single cleanout at teardown. Anyone planning a festival restroom rental or concert restroom rental in St. Louis should build that second service into the quote up front. Golf outings and fairs run lighter traffic per hour but longer days, so check golf tournament restrooms or county fair restrooms for pacing guidance specific to those formats.
Yes. A one-day count assumes units get serviced once at the end. Stretch the same guest list across three days and you either add units or add service visits, since a 60 to 70 gallon tank fills faster under sustained multi-day use than a single afternoon. Alcohol service compounds this: a beer garden running all three days of a festival should plan for the higher per-guest ratio in the table above, applied each day, not averaged across the event. For anything running past a single weekend, ask St. Louis Porta Pros about a swap schedule rather than trying to stretch capacity with more units alone. Renovation projects have a similar issue: a homeowner doing a home renovation porta potty rental for a 6-week project needs a single unit but a regular service cycle, not a one-time drop.
A 60-person crew falls in the 40 to 59 worker bracket under OSHA 1926.51(c): 2 toilet seats and 2 urinals minimum. In practice, most crews round up to 3 standard porta potty rental units to cover breaks without a line, especially with 10-hour shifts extending the daily window. If any trade on site is spraying coatings or pesticides, add a wash station to satisfy 1926.51(f)(1) separately from the toilet count. Potable water also has to be on site under OSHA 1926.51(a)(1), regardless of toilet count. A crew this size working a job near University City, 7.9 miles northwest of St. Louis, or out toward Kirkwood, 12.5 miles west, faces the same bracket math since the rule doesn't change by location, only delivery logistics do. Check porta potty rental cost for what 3 units run over a multi-week job.
At 200 guests with an open bar running 6 hours, use the higher alcohol ratio: roughly 1 unit per 35 to 40 guests, landing at 5 to 6 standard units, or consider a 4 stall restroom trailer instead of scattering individual units across the venue. At least one accessible unit is needed per ADA Standards 213.2, and ADA Standards 404.2.3 requires a 32 inch clear door opening on that unit so a wheelchair user can get through comfortably. If the venue sits near Webster Groves, 8.6 miles southwest of St. Louis, or Chesterfield, 19.2 miles west, factor that drive into your delivery window when booking, since delivery fee bands vary with distance and timing. A deluxe flushable porta potty upgrade is common for weddings where guests expect something nicer than a construction-grade unit.
Only if you're running a full site setup, but the two decisions often happen together. A 10 yard dumpster rental runs about 12 feet long and holds roughly 10 cubic feet, sized for smaller cleanouts, and people asking how many cubic feet in a 10 yard dumpster are usually comparing it against a 20 yard dumpster rental, which holds about double that at roughly 20 cubic feet and measures around 22 feet long, so how many feet is a 20 yard dumpster comes down to that same 22-foot figure. How many tons does a 20 yard dumpster hold typically lands around 2 to 3 tons, while how many tons can a 30 yard dumpster hold usually runs closer to 4 to 5 tons depending on material density. A 40 yard dumpster rental is the largest standard option, and how many tons does a 40 yard dumpster hold depends heavily on what's inside, though it typically carries the most tonnage of the four since debris density varies more than volume does. Check dumpster sizes and dimensions or dumpster weight limits before ordering, and pair the container with construction site services planning so delivery trucks for both the dumpster and the toilets aren't fighting over the same site access.
For 100 guests over a 4 hour event with no alcohol, plan on 2 standard units. Add a bar and that climbs to about 3, since alcohol increases bathroom trips per guest. A construction crew of 100 falls into a different bracket entirely under OSHA 1926.51(c).
Fifty workers on a construction site falls into the 40-worker OSHA bracket, requiring 1 toilet seat and 1 urinal minimum, though most crews add a second unit to avoid line-ups during breaks. This is a jobsite ratio, not an event ratio.
ANSI/PSAI Z4.3 sets a baseline of once weekly for up to 10 users across a 40 hour week. Heavier traffic, multi-day events or alcohol service all shorten that interval, so ask about a mid-week or mid-event swap for busy sites.
Yes, if units are clustered together. ADA Standards 213.2 requires at least 5 percent of a cluster to be accessible, with a minimum of one unit regardless of total count, even for a 2 or 3 unit setup.
A 30 yard dumpster typically holds a bit less tonnage than a 40 yard, since the 40 yard has more cubic footage for the same material. Actual weight depends heavily on what's thrown in, so check dumpster rental cost for guidance on your specific debris type.
Yes, noticeably. Alcohol service increases restroom visits per guest, so the standard 1-per-50 ratio tightens to roughly 1 per 35 to 40 guests once a bar opens, and that adjustment applies across full event duration, not just peak hours.
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