Yes, in most small spaces. In Phoenix, single-user restrooms don't have to be split by sex, they count toward the required fixture total, and tenant spaces with 15 or fewer occupants need no separate men's and women's rooms. The count for your use and the ADA rules still apply.
What does the plumbing code say about single-user rooms?
Phoenix's version of the International Plumbing Code (Section 403.2) starts with the general rule that separate toilet facilities are provided for each sex, then lists exceptions. Four matter to a small tenant:
- Structures or tenant spaces with a total occupant load of 15 or fewer, employees and customers combined.
- Mercantile occupancies with a maximum occupant load of 50 or fewer.
- Business occupancies with a maximum occupant load of 50 or fewer.
- Single-user toilet rooms, and rooms with both water closets and lavatories designed for all persons regardless of sex, with privacy for water closets and urinals.
The plumbing code's Section 403.1.2 covers the counting. Fixtures in single-user toilet and bathing rooms "contribute toward the total number of required plumbing fixtures for a building or tenant space," and those rooms must be identified as available to all persons regardless of sex.
Mesa's plan checklist has its own version of the exception, listed as "Small occupancies 25 or less" (Mesa IPC 403.2). That threshold is lower than Phoenix's 50 for business and mercantile uses, so a Mesa tenant with 30 occupants can't rely on it.
How many single-user rooms does a small space actually need?
That depends on the occupant load and the ratios in the commercial fixture count table. Single-user fixtures count toward the total, so a small office with one or two rooms can meet a small count. The plan reviewer, not a rule of thumb, sets the final number, because the count depends on the use, the occupant load and the code edition the city has adopted. Bring the occupant load calculation to the pre-submittal conversation.
Bigger tenants usually switch to a multi-user, all-gender room. The code allows that too, if the room gives privacy at each water closet and urinal, and the ICC's summary of Section 403.1.1 says the fixture count for such a facility can be figured on 100 percent of the total occupant load instead of half and half. At 15 or fewer occupants, Phoenix drops the sex-split rule altogether, so the reviewer sets the count from the occupant load and the table's minimum of one fixture per fraction of the ratio.
Restaurants also answer to Maricopa County Environmental Services, so ask the county's plan reviewer how it wants employee and customer toilet facilities shown.
Does a single-user restroom still need to be accessible?
Yes. The 2010 ADA Standards say toilet rooms comply with Section 603, and a unisex (single-user) toilet room "shall contain not more than one lavatory, and two water closets without urinals or one water closet and one urinal," with a privacy latch on the door. Only the plumbing count relaxes for a single-user room. Turning radius, grab bars, fixture heights and clearances are the same as any accessible restroom, and our page on ADA commercial restroom plumbing has the numbers.
Mesa's checklist also flags a separate accessibility rule: assembly and mercantile occupancies with six or more water closets need an accessible family or assisted-use toilet room. A small tenant space rarely hits that number.
### What about a larger all-gender room with several stalls?
The code also allows a multiple-user all-gender facility, and the counting changes. The occupant load is not split into male and female halves. The fixture count can be figured at 100 percent of the occupant load. The trade-off is privacy. The International Plumbing Code calls for a separate compartment with walls or partitions and a door for each water closet, and a separate area with walls or partitions that provide privacy for each urinal. Each fixture that has to be accessible must also meet the ICC A117.1 standard. A design can mix and match, too. The total can be based on the number of separate facilities, or on any combination of separate, single-user and all-gender facilities.
### Does a single-user room save space?
Often, yes. A single-user room has its own door, so it does not need the separate entry vestibule or the two sets of partitions that a pair of men's and women's rooms would. One room can serve any customer or employee, including someone who needs help from a companion of another sex. The cost is that fewer people can use the restroom at once. Two single-user rooms serve two people at a time, while one larger room with several stalls serves more in the same footprint. For a small office, salon or clinic the single-user approach usually wins. For a busy restaurant, count the rooms against the peak crowd, not just the code minimum.
### How should the rooms be labeled?
The plumbing code's rule is that single-user toilet rooms must be identified as available to all persons regardless of sex. That is why a small tenant's plans show a single-user room with an all-gender sign instead of a men's or women's symbol. Accessibility signs are a separate rule. Under ADA Section 216.8, directional signs with the International Symbol of Accessibility are required only where existing toilet rooms or bathing rooms do not comply with Section 603. Ask the plan reviewer which signs they want to see on the drawings, since the exact sign details can be set locally.
### What about an existing space where the room cannot be enlarged?
The ADA has a relief valve for alterations. When it is technically infeasible to bring an existing toilet room up to the accessible standard, a single unisex toilet room can be substituted, and qualified historic buildings get a similar option of one room per sex or one unisex room. The ADA definition of a unisex toilet room is short and worth knowing: not more than one lavatory, and either two water closets without urinals or one water closet and one urinal. Where you have a cluster of single-user rooms, the standards do not require every one to be accessible: no more than 50 percent of the rooms in the cluster, per use, have to comply. These exceptions are narrow. Have the building official or an accessibility consultant confirm which ones apply before you rely on them.
What's the practical answer for a small tenant?
Bring these answers to the first meeting with the architect or plan reviewer: the occupant load, the use group, how many single-user rooms the count calls for, and whether the room will be new construction or an alteration of an existing one. Those four facts decide almost every other question on this page. Three steps cover it:
- 1Get the occupant load and use classification from the architect or plan review.
- 2Run the fixture ratio, then check the small-space exceptions for your city. At 15 or fewer occupants, the sex-designation question disappears in Phoenix.
- 3Draw the restroom as an accessible single-user room. It's usually the simplest layout to get through review, and it works for any occupant, employee or customer.
A business with only one restroom has less room for an outage, as our page on staying open with restrooms out of service explains.
A larger warehouse or industrial space follows different counts, as our page on adding a restroom to a warehouse shows.
If you're framing out a lease space, commercial tenant improvement plumbing shows where the restroom sits in the bigger scope. HQ is licensed and insured and gives free estimates on commercial restroom work.