Occupancy limits and how many restrooms you need

Two numbers govern the front of house, and they are linked: how many people you may legally hold, and how many fixtures that number requires. Get the first wrong and the second is wrong too, which is how a plan set comes back asking for a bathroom you have nowhere to put.

Neither of these is in the food code. Occupancy is the Ohio Building Code and fixtures are the Ohio Plumbing Code — so your health district will not raise them, and by the time your building department does, the walls are drawn.

Both are adopted by rule rather than written from scratch: Ohio takes the 2021 International Building and Plumbing Codes and modifies them.¹² That matters for two reasons. The tables below are the ones Ohio actually enforces — we checked the adopting rules, and Ohio’s egress modifications do not touch the occupant load table.¹ But Ohio does modify the plumbing chapter in several places that change what you build, and those are flagged below where they apply.

Occupant load

The number of occupants is the floor area divided by an occupant load factor assigned to the function of that space.³ Where a space has several functions, each is calculated independently and the results added.³

Net is the actual occupied area and excludes corridors, stairways, toilet rooms, mechanical rooms and closets. Gross is measured to the inside face of exterior walls.

So a 3,000 square foot dining room with tables and chairs is 3,000 ÷ 15 = 200 occupants, and a 1,400 square foot kitchen adds 1,400 ÷ 200 = 7 more.

The factors are the design lever. The same room seats 200 with tables, 428 with chairs alone, and 600 as standing space. A concept that puts a standing bar area in the corner has changed its occupant load — and therefore its egress and its fixture count — without moving a wall.

Going above the calculated number

You may increase the occupant load, provided every other code requirement is met at the higher number and the load does not exceed one occupant per 7 square feet of occupiable floor space.³ The building official may require an aisle, seating or fixed equipment diagram to substantiate it — and may require that diagram to be posted.³

That is the ceiling. There is no route to a higher number than one person per 7 square feet.

Restrooms — and the difference that catches people

Fixture counts come from Table 403.1 of the Ohio Plumbing Code.⁴ Ohio’s only change to the table itself concerns a footnote about swimming pools, so the ratios below are the ones enforced here.² Both restaurants and bars are Assembly Group A-2, but they sit in different rows:

A bar needs roughly twice the water closets and nearly three times the lavatories of a restaurant with the same occupant load. At 200 occupants — 100 of each sex, as the code assumes — a restaurant needs 2 water closets and 1 lavatory. A bar needs 6 water closets and 3 lavatories.

That is a materially different bathroom, and it is decided by what your concept is called, not by its square footage.

Which is the trap. Concepts drift during design. A restaurant with a good bar program becomes a bar with food; a taproom adds a kitchen. If the classification your plans were drawn against stops matching what you are actually opening, the fixture count moves — and adding a water closet late means opening a floor, not hanging a door. Settle the classification with your building department before the plumbing is roughed in, and if the concept is genuinely between the two, ask them in writing which row applies.

Urinals may substitute for a portion of the required water closets, subject to the table’s own footnotes — worth raising with your designer, because it is usually the cheapest way to close a gap.⁴

The Ohio amendments that change the answer

Four modifications Ohio makes to the plumbing chapter, none of which appear in the national table:²

1. The building official can set an alternate occupant load for fixture purposes. Where the actual occupant load will be significantly different from the building-code calculation, the building official may establish an alternate basis — and it goes into the special stipulations and conditions section of your certificate of occupancy.²

That is the escape hatch for a room whose calculated load bears no relationship to how it will be used. It is a conversation with the building official, in advance, and the result is written on your certificate rather than agreed on a handshake.

2. The route to public toilets may not pass through the kitchen — nor through storage rooms, closets, or similar spaces not available to the public.⁴² A back-corner restroom reached past the dish pit is a plan-review problem, and it is a common one in narrow older buildings.

You may control access to the restrooms — but where you do, a sign must be posted saying how access is obtained.⁴²

3. Where drinking fountains are required, Ohio requires not fewer than two.² The table says one per 500; the modification sets a floor of two wherever any are required at all.

4. But restaurants that give away water may not need one. Where a restaurant provides drinking water in a container free of charge, drinking fountains are not required.⁴ That is most table-service restaurants in this market, and it is worth raising before a fountain gets drawn into a corridor.

One more, useful for small footprints: facilities are not required in buildings under 100 square feet if fixtures are available within 500 feet.²

Soap, towels, sanitizer and where they go

This part is the food code, and it is more specific than most operators expect.

Every handwashing sink, or each group of two adjacent ones, needs:⁶

• Hand cleaning liquid, powder or bar soap
• A drying method — individual disposable towels, a continuous clean-towel system, a heated-air dryer, or an air-knife device
• A waste receptacle, where disposable towels are used
• Handwashing signage, clearly visible to food employees

And the rule that reads backwards until you think about it: a food prep sink, a utensil sink, or a service or mop sink may not be provided with those handwashing aids.⁶ Putting a soap dispenser over the prep sink does not create a handsink. It creates a violation, because it invites the sink to be used as one.

Where handsinks go is a location requirement, not a count: conveniently located for use in food preparation, food dispensing and warewashing areas, and in or immediately adjacent to toilet rooms — and never fewer than the Ohio Plumbing Code requires.⁵ They must be accessible at all times and may only be used for handwashing.⁵

You also need at least one service sink or curbed cleaning facility with a floor drain, conveniently located, for mops and mop water.⁵ That is separate from everything above.

Hand sanitizer is not a substitute

Ohio treats a hand antiseptic as something applied only to hands that have already been cleaned by the full procedure.⁷ Where an antiseptic does not meet the food-additive criteria in the rule, its use has to be followed by a thorough rinse in clean water before bare-hand contact with food, or limited to situations with no direct food contact.⁷

Sanitizer by the door is a fine courtesy for guests. It does not reduce the number of handwashing sinks you need, and it does not shorten the twenty-second procedure.

What to settle before the drawings are final

1. Calculate the occupant load by function, not as one number for the whole floor — dining, standing bar, kitchen and storage are separate arithmetic.
2. Decide whether you are a restaurant or a bar in the plumbing code’s eyes, in writing, before the plumbing is roughed in.
3. Check the fixture count against the occupant load you actually want, not the one that fits the bathroom you already have.
4. Ask whether urinals can close any gap before redesigning.
5. Put a handsink in every area the food code names — prep, dispensing, warewashing, and by the toilet rooms — and confirm nobody has hung soap over a prep or mop sink.
6. If you plan to push occupancy up, ask the building official early whether they will want a diagram, and whether it has to be posted.

Occupancy and plumbing are building department matters, not health district ones, and the specifics turn on your drawings and your municipality. Confirm with the authority having jurisdiction — and see where things go in a commercial kitchen for the back-of-house side of the same plan set.