Chicago Construction Site Toilet Requirements

Most contractors in Chicago know there is an OSHA ratio for job site toilets. Fewer know that the Chicago Plumbing Code sets its own ratio, that it is stricter than OSHA's at some crew sizes, and that it makes it unlawful to begin work without proper and sufficient toilet facilities in place. On a job site in the city you are working to both rules at once.

Below: what the federal standard says, the Chicago section that catches people out, servicing frequency, placement, and what changes once the temperature drops.

What OSHA 1926.51 requires

The construction sanitation standard is 29 CFR 1926.51. Paragraph (c), "Toilets at construction jobsites", sets the counts in Table D-1:

• 20 or fewer employees: one facility.
• 20 or more employees: one toilet seat and one urinal per 40 workers.
• 200 or more employees: one toilet seat and one urinal per 50 workers.

The first two rows overlap at exactly 20. That is how the rule is written. The working interpretation almost everyone applies is that a crew of 20 or fewer needs one facility, and above 20 you provide one toilet seat and one urinal per 40 workers, moving to per 50 at 200 and above.

Three further parts of paragraph (c) matter on real sites:

• (c)(2) requires that under temporary field conditions, provisions be made to assure not less than one toilet facility is available.
• (c)(3) covers sites with no sanitary sewer. Unless local codes prohibit them, those sites must be provided with privies (where their use will not contaminate ground or surface water), chemical toilets, recirculating toilets or combustion toilets. A standard portable toilet is the chemical toilet option, and on most Chicago job sites it is the only practical one of the four.
• (c)(4) exempts mobile crews with transportation readily available to nearby toilet facilities. This is narrower than it sounds: a crew parked on one address all week is not a mobile crew, and a coffee shop two blocks away that may or may not let them in is not readily available.

Washing facilities and drinking water get missed

Paragraph (f) deals with washing facilities, and it is the part most often overlooked at pre-start. Paragraph (f)(3) requires that lavatories be made available at all places of employment, with the same mobile crew and unattended location exception as the toilet rule. Each lavatory must have hot and cold running water, or tepid running water. Hand soap or a similar cleansing agent must be provided, and individual hand towels of cloth or paper, sections of clean continuous toweling, or air blowers must be conveniently located near the lavatory. Paragraph (f)(2) requires washing facilities be maintained in a sanitary condition.

Paragraph (f)(1) is separate and stricter in scope: the employer must provide adequate washing facilities for employees engaged in the application of paints, coatings, herbicides or insecticides, or other operations where contaminants may be harmful. Those facilities must be in near proximity to the worksite and equipped so employees can remove the substances.

In practice a portable handwashing station with fresh and wastewater tanks, soap and paper towels is how this gets provided. The sanitizer dispenser inside a porta potty is not a lavatory.

Paragraph (a) covers potable water: an adequate supply in all places of employment, portable containers that can be tightly closed and have a tap, containers labelled and used for nothing else, no common drinking cup, and where single use cups are supplied, a clean holder for unused cups and a receptacle for used ones.

The Illinois layer

Two points on state law. First, enforcement: Illinois does not run a state OSHA plan covering private sector employers, so a private construction site in Chicago is inspected under federal OSHA. The state plan covers state and local government employees.

Second, Illinois has its own statute on the subject, the Construction Site Temporary Restroom Facility Act at 410 ILCS 37, which places a duty on the owner or the owner's representative of a temporary building or a building under construction to see that employees on site have access to restroom facilities, and ties facility counts to the OSHA construction sanitation standards. The Act was amended in 2026 by Public Act 104-0850, which renamed it and added requirements including a separate designated toilet facility in defined circumstances where women or people who menstruate are working on the site.

Because that amendment is recent, do not plan from a summary, including this one. Read the current statutory text or have your counsel confirm what applies to your site and from what date.

Counting your crew honestly

The ratios apply to people on site, not to your payroll. Three things trip up the count:

• Subcontractors. On a day when the framers, the electricians and the mechanical crew are all on site, every one of those people is using your units. Count the peak day, not the average.
• Crew growth. Headcount is not flat. It climbs through rough-in and peaks during finishes, so a count that was right in month one is often short by month four.
• Visitors and inspectors. Not a large number, but on a site with one unit it is the difference between available and occupied.

Recount when the trades stack. Adding a unit mid-job is a phone call; a citation or a crew walking off site to find a restroom costs more.

How often units should be serviced

OSHA does not set a service interval. It sets how many facilities you provide and, for washing facilities, that they be kept sanitary. Frequency is a practical question with a compliance consequence if you get it wrong.

The common baseline across the industry is one service visit per week per unit at roughly ten workers per unit. Move above that density and weekly stops being enough. The situations that reliably need twice weekly or more are high crew counts per unit, hot weather, units that are locked overnight and unventilated, and sites where the unit is the only facility for a long shift.

A service visit means pumping the tank, recharging it with fresh deodoriser solution, restocking paper and wiping down the interior. What it cannot fix is a tank full of debris. Drywall offcuts, cups, gloves and bottles will stop a vacuum hose, and the unit then stays out of service until it is swapped. One toolbox talk at the start of the job saves several of those.