Does a small Mesa business need separate men's and women's restrooms? IPC 403.2 and 410.2

The amendments sit in City Code 4-5-2 and change three parts of the base IPC:

• Separate facilities, 403.2 Exception 2. "Separate toilet facilities shall not be required in structures or tenant spaces with a total occupant load, including both employees and customers, of 25 or fewer." A space at or under 25 need not separate toilet facilities by sex; the required fixture count still comes from the applicable table. The other 403.2 exceptions are the base IPC text, which Mesa did not amend.
• Service sinks, Table 403.1 footnote e. "For businesses and mercantile classifications with an occupant load of 100 or fewer, a service sink shall not be required."
• Drinking fountains, 410.2. "Drinking fountains shall not be required for an occupant load of 50 or fewer."

The city's plumbing plan checklist repeats these under Plumbing Facilities. Item 1a says service sinks are not required for Groups B and M where occupant loads do not exceed 100 persons. Item 3a gives the small occupancy exception at 25 or less. Item 8b exempts drinking fountains at occupant loads of 50 or less.

One catch: a sample calculation on the last page of the city's checklist says a service sink is not required for B and M occupancies with an occupant load of 15 or fewer. That does not match the 100 in the code text and in item 1a. The code text controls, so have Development Services review the plan against the adopted code if it relies on the threshold.

• Occupant load. The number of people the space is designed to hold, worked out under the building code, not the number of staff.
• Total occupant load. For the 25 exception, employees and customers counted together.
• Tenant space. One tenant's suite within a larger building.
• B and M. Business and mercantile occupancy groups, such as offices and retail stores.

Small shops, offices, salons, clinics and restaurants in Mesa whose plans rely on the occupant load, and the landlords and architects who lay them out. It covers plumbing fixture counts only. Accessibility rules are separate, and the ADA restroom guide explains how they interact.

The rows follow the three thresholds above. Mesa amended only Exception 2 of 403.2, which is the 25 or fewer line. The base IPC exceptions still apply as printed, including Exception 3 for mercantile occupancies with a maximum occupant load of 100 or fewer, Exception 4 for business occupancies at 25 or fewer, and the single-user room exceptions. Tempe, by comparison, moved Exceptions 2, 3 and 4 all to 30. A space that misses one line can still use the others.

A 20-person office suite. With a total occupant load of 20, the suite can use a single-user restroom instead of two, and needs no fountain or service sink.

A 40-person clinic. The load is over 25, so separate facilities are required unless another 403.2 exception or permitted single-user layout applies. It is under 50, so no drinking fountain is required, and under 100, so no service sink in a B occupancy.

The edge case. A retail store with 60 occupants. It is over 25, so Mesa's Exception 2 no longer applies, but the base exception for mercantile occupancies at 100 or fewer still does, so separate facilities are not required. A Group B office with 60 occupants must use the general separate-facilities rule or a different applicable exception, such as a compliant single-user layout. Occupancy group matters as much as the head count.

1. 1Calculate the occupant load from the floor plan and use, following the building code.
2. 2Compare it with 25, 50 and 100 to see which exceptions apply.
3. 3Put the load and the fixture count on the plumbing plan sheet, since the checklist asks for the occupancy load or minimum fixtures.
4. 4Check the fixture count against Table 403.1 for the occupancy group if you are above 25.
5. 5Submit with the rest of the commercial packet through Mesa Development Services.

• "25 means 25 employees." The count is total occupant load, employees and customers together.
• "Over 25 means separate restrooms." Exception 2 is only one of the exceptions. Mercantile occupancies up to 100 and single-user room layouts have their own.
• "One threshold covers everything." The three amendments use 25, 100 and 50.
• "The checklist sample is the rule." Its 15 or fewer figure for service sinks conflicts with the code text.
• "Small space means no accessibility rules." Those are separate from the plumbing fixture count.