Michigan construction sites are counted under MIOSHA construction Rule 129, which ties the number of toilets to headcount. The count below comes from a 2008 legislative summary of that rule, so the current rule text should be read before a site plan depends on it.
Key takeaways
- MIOSHA construction Rule 129 (R 408.40129) ties toilet numbers to headcount, and the units are to be serviced and supplied.
- The 2008 legislative summary describes one toilet for 1 to 20 employees, two for 21 to 40, then one more for each 40 or fewer beyond that.
- Mobile crews with transport are treated differently under the summary, but whether a given crew qualifies is a site-by-site question.
- A 2007 bill proposing one toilet per ten workers was not found to have been enacted, so the current text must be checked.
- Federal construction rules in 29 CFR 1926.51(c) also set counts by headcount. Read that section directly rather than a summary.
- Large road and bridge work in the city is a good example of where crew counts, and so unit counts, run high.
Does Michigan set a toilet count for construction?
Yes. MIOSHA construction Rule 129 sets toilet numbers by headcount, and the units must be serviced and supplied. The count in this guide is taken from a 2008 legislative analysis of the rule, so the current text needs checking before a plan relies on it.
Construction toilets in Michigan are governed by workplace safety rules rather than by the portable-toilet trade, and the count follows the crew, not the building. The rule is written around the number of employees on site, so a crew of ten and a crew of forty need different plans even on the same job.
The count used here comes from a legislative analysis dated 2008, which summarized the rule as it then stood. The analysis is a useful guide to the structure of the rule, but it is a secondhand summary, and the rule may have been amended since. The state’s own text is the reference a site plan should cite.
A practical way to use this is to build the plan from the current rule, check the headcount for each shift, and then ask the provider to confirm that the units ordered meet the count for the largest shift, not the average day.
What do the headcount steps look like?
The summary describes one toilet for one to 20 employees, two for 21 to 40, and one more for each 40 or fewer beyond that. The units must be serviced and supplied throughout the job.
Read the steps as a ladder. A crew of up to twenty needs one unit. Once the crew passes twenty, a second unit is required, and each further block of forty adds one more. The step is taken at the headcount, so a site that grows from twenty to twenty-one changes its count on the day it does.
The summary also describes the units as serviced and supplied. Servicing is not optional and it is not a matter for the provider to decide alone: the plan should name the visit frequency and who checks that a unit is supplied with paper and water between visits.
A 2007 bill, House Bill 5064, proposed one toilet for every ten workers. No result showed it enacted, and this guide does not treat it as the current rule. It is mentioned so that a planner who finds it knows why it is not used here.
| Employees on site | Toilets required (per the summary) |
|---|---|
| 1 to 20 | 1 |
| 21 to 40 | 2 |
| Each further 40 or fewer | 1 more for each block |
What about crews that move from site to site?
Mobile crews are treated differently in the summary, and transport can be exempt from the count where the crew travels between sites. Whether a particular crew qualifies is a site-by-site question, not a yes or no this page can give.
A mobile crew paving a corridor, repairing a bridge deck or stringing line between stations does not stay in one place for long. The summary recognizes that movement and treats transport differently, so a crew that travels with its own facilities may need a different plan from a crew that stays on one lot all season.
The test is what the crew actually does on the day. A crew that works a fixed site for a month will be counted as a site. A crew that moves each day, and has transport to reach facilities, can be treated as mobile. Write down how the crew moves, so the plan can show why a count is or is not needed at each stop.
Federal construction rules in 29 CFR 1926.51(c) also set toilet counts by headcount. This guide does not reproduce those figures, because the summary available here was secondhand. Read the section directly before a plan is finalized.
Which Michigan road and bridge projects are likely to need units?
Several large projects were reported for 2026 and later in the city. They show where crew numbers, and so unit counts, are likely to run high. They are examples, not a list of sites whose contractors this page knows.
The I-94 rebuild between I-275 and Michigan Avenue has been reported as running through 2029. A project of that length needs a count that is reviewed as the crews change, and units that are serviced on a schedule that outlasts any single phase.
Michigan Avenue in Corktown, from Cass Avenue to I-96, was reported as a reconstruction for 2026, and the Gratiot Avenue bridge over the Dequindre Cut was reported for summer 2026 through February 2027. The I-696 eastbound closure was reported as running until November 2026, with the work 37 percent complete according to MDOT.
These timings are reported figures, not confirmed schedules for any one contractor. A planner should check the current schedule with the agency and the contractor before ordering units, because the count depends on the crew on the day, not on the project name.
What should a construction order say?
A useful order names the headcount by shift, the number of units, the servicing schedule and the access route. That lets the count and the service plan be checked against the rule, rather than against an estimate.
Start with the headcount for each shift and the largest shift in the schedule. The count has to meet the largest shift, not the average, because that is when a unit is most likely to be short. Name the number of units for each stage of the job.
Name the servicing: how often each unit is serviced, who checks the supply of paper and water between visits, and how an extra visit is requested when the site is busy. Include the route the truck uses and any gate or closure that affects the placement.
Finally, name the waste handling. The contents are septage under Michigan’s rules, so the order should say which hauler collects the waste and how that hauler’s licenses can be checked. The waste rules guide sets out the check.
Frequently asked questions
Is the 2008 count still the rule?
This guide cannot confirm it. The summary is from 2008, a 2007 bill proposing a different ratio was not found to pass, and the current text of Rule 129 is what applies. Read it on the state’s website before finalizing a plan.
Does a site with three workers need a toilet?
The summary places one toilet at the bottom of the headcount range, so a site with one to 20 employees is counted as needing one unit. Confirm the count for your own site and whether the crew is mobile.
Who is responsible for servicing the units?
The summary describes units that are serviced and supplied, but it does not settle who does that on a given job. The order should say who services the units, how often, and who checks the supplies between visits.
Does the federal standard set a different count?
Federal construction rules in 29 CFR 1926.51(c) also set toilet numbers by headcount. The figures are not reproduced here, so read that section directly and compare it with the state rule before ordering.
Sources
- State of Michigan: MIOSHA construction safety standards
- Michigan Legislature: Michigan legislative analyses and statutes
This guide is general information for Wayne County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.