Federal OSHA rules set the floor for how many restrooms are required in a business: one toilet for up to 15 employees, two for 16 to 35, three for 36 to 55, and up from there. That covers your workers. If customers, patients, or other visitors use the space, local plumbing codes add fixtures on top based on the building’s total occupancy. The final number for any given business is where those two rules meet, filtered through whatever version of the model codes your city or county has adopted.
The OSHA Minimum by Employee Count
The Occupational Safety and Health Administration requires every employer to provide sanitary, immediately available toilets. The count is tied to how many people you employ, not how big the building is or how many customers walk through. Table J-1 under 29 CFR 1910.141 lays it out:
- 1 to 15 employees: 1 toilet
- 16 to 35 employees: 2 toilets
- 36 to 55 employees: 3 toilets
- 56 to 80 employees: 4 toilets
- 81 to 110 employees: 5 toilets
- 111 to 150 employees: 6 toilets
- Over 150 employees: 1 additional toilet for every 40 employees beyond 150
OSHA requires separate restrooms for men and women. Where restrooms won’t be used by women, urinals can substitute for some toilets, but at least two-thirds of the minimum count has to stay actual toilets.1eCFR. 29 CFR Part 1910 Subpart J – General Environmental Controls
When One Restroom Can Serve Everyone
The separate men’s and women’s rule has an exception. Under OSHA, a single-occupancy restroom that locks from the inside and contains at least one toilet can serve both sexes without a duplicate facility.1eCFR. 29 CFR Part 1910 Subpart J – General Environmental Controls
Plumbing codes give small businesses a similar break. Under the standard International Plumbing Code, businesses with a total occupant load of 15 or fewer are not required to provide separate men’s and women’s restrooms. For business occupancies specifically, the threshold is often 25 or fewer. A single lockable restroom satisfies the requirement in those cases.2International Code Council. Chapter 4 Fixtures Faucets and Fixture Fittings – 2021 International Plumbing Code
Some jurisdictions have raised those thresholds, so check the adopted code where you operate. If you qualify, one well-designed unisex restroom can replace two separately plumbed rooms.
How Customers Change the Count
OSHA’s table stops at employees. Building and plumbing codes pick up everyone else in the space. The starting point is a number called the occupancy load, meaning the maximum number of people the space is designed to hold at once.
The International Building Code assigns each type of use a factor. Divide the floor area by the factor and you get the occupancy load. Some common examples:
- Office space: 150 gross square feet per person. A 3,000-square-foot office has an occupancy load of 20.
- Retail (general mercantile): 60 gross square feet per person.
- Restaurant with tables and chairs: 15 net square feet per person.
Gross area includes hallways, closets, and mechanical rooms. Net area excludes those, which is why dining and assembly spaces use a tighter per-person figure. For fixed-seating spaces like theaters, the occupancy load equals the number of installed seats.3International Code Council. Chapter 10 Means of Egress – 2018 International Building Code
Once you have the occupancy load, the IPC’s Table 403.1 tells you how many toilets and sinks that number of people needs. The ratio depends on business type.
Offices
For a standard business occupancy, the IPC requires one toilet per 25 occupants for the first 50 people, then one toilet per 50 occupants beyond that. Lavatories follow a similar step: one sink per 40 occupants for the first 80, then one per 80 after that. A 100-person office needs at least three toilets and two sinks.4International Code Council. Chapter 4 Fixtures Faucets and Fixture Fittings – 2021 International Plumbing Code
Restaurants and Bars
Dining spaces fall under assembly occupancy. Customers stay longer and the space packs more people per square foot, so the ratios tighten. A restaurant dining room typically requires one toilet per 75 occupants. Bars with fixed seating need roughly one per 40. A 2,000-square-foot dining room at 15 net square feet per person carries an occupancy load of about 133, and fixture counts climb fast from there.5International Code Council. Chapter 4 Fixtures Faucets and Fixture Fittings – 2018 International Plumbing Code
Retail
Mercantile occupancies get the most generous ratios because customers move through quickly. Even so, the 60-square-foot-per-person occupancy factor means a large store still builds up a real occupancy load, and a big-box space will need more than one restroom.5International Code Council. Chapter 4 Fixtures Faucets and Fixture Fittings – 2018 International Plumbing Code
The occupancy load is split between men and women when calculating fixtures for each restroom. Fractions round up. If the math gives you 2.1 toilets, you install three.
Construction Sites
Construction has its own OSHA standard at 29 CFR 1926.51, with a different ratio:
- 20 or fewer workers: 1 toilet
- More than 20 workers: 1 toilet seat and 1 urinal per 40 workers
- 200 or more workers: 1 toilet seat and 1 urinal per 50 workers
Where there’s no sanitary sewer, portable chemical toilets, recirculating toilets, or combustion toilets satisfy the rule. Mobile crews with ready transportation to nearby facilities are exempt from on-site toilets, provided those facilities are genuinely accessible without unreasonable delay.6eCFR. 29 CFR 1926.51 – Sanitation
The ADA Does Not Add Restrooms
A common misconception is worth clearing up. The Americans with Disabilities Act does not tell you how many restrooms to build. The 2010 ADA Standards for Accessible Design require that where toilet rooms are provided, each one comply with the accessibility requirements in Section 603.7ADA.gov. 2010 ADA Standards for Accessible Design The plumbing code determines the count. The ADA shapes how those restrooms are built.
One count-related wrinkle: if your building has a cluster of single-user restrooms in one location, no more than 50 percent of them need to meet the full accessibility requirements. For portable toilet clusters at events or construction sites, only 5 percent need to be accessible, and those must display the International Symbol of Accessibility.7ADA.gov. 2010 ADA Standards for Accessible Design
Keeping the Restrooms You Have Compliant
A restroom on the floor plan isn’t the same as a restroom OSHA counts. Each one must include a lavatory with hot and cold (or tepid) running water, hand soap, and either paper or cloth towels or an air dryer.1eCFR. 29 CFR Part 1910 Subpart J – General Environmental Controls Restrooms have to stay sanitary, and waste has to be removed often enough to prevent health hazards.8Occupational Safety and Health Administration. 1910.141 – Sanitation
Employers also can’t impose unreasonable restrictions on restroom use. No locked doors with delayed key-checkout, no policies that punish employees for going, and no forcing production-line workers to wait unreasonably long for relief coverage.9Occupational Safety and Health Administration. Restrooms and Sanitation Requirements
What Non-Compliance Costs
OSHA penalties for inadequate or unsanitary restrooms reach up to $16,550 per serious or other-than-serious violation, with willful or repeated violations substantially higher. Amounts are adjusted annually for inflation.10Occupational Safety and Health Administration. OSHA Penalties
ADA violations run on a separate track. The Department of Justice can seek civil penalties of up to $75,000 for a first violation and $150,000 for subsequent violations, and private lawsuits can force costly retrofits. Building code violations can delay or halt construction, and operating without required fixtures can lead to fines, loss of an occupancy permit, or forced closure until the space is brought into compliance.
Check Your Local Code Before You Build
The federal and model-code numbers above are the baseline. Your actual obligations depend on the edition of the IBC and IPC your city or county has adopted, plus any local amendments. Some jurisdictions require more fixtures per occupant than the model code. Others set different thresholds for when separate men’s and women’s restrooms become mandatory. Where state or local accessibility standards exceed the ADA, the stricter standard applies.11ADA National Network. What Should Be Applied to a Situation When Both the Local or State Code and the 2010 ADA Standards for Accessible Design Need to Be Considered
Call your local building department before you commit to a floor plan. Ask which edition of the plumbing code is in force and whether there are local amendments. Finding out that your jurisdiction wants an extra restroom after the walls are framed costs a lot more than the phone call.