3.1 Minimum Plumbing Facilities: Table 403.1, Calculations & Separate Facilities

Why fixture counts are tested

Plumbing Fixtures is a 7-item outline area. The most common calculation asks for the number of water closets or lavatories in a building. You need three skills: find the right Table 403.1 row for the actual use, divide the occupants correctly, and round correctly. Virginia amended Table 403.1 and several subsections (VCC 2901.1.1, items 5 to 17), and those changes appear below.

Step 1: occupant load (IPC 403.1)

Fixtures are provided "based on the actual use of the building or space," and "the number of occupants shall be determined by the International Building Code." The IBC divides floor area by the occupant load factors in IBC Table 1004.5. Common 2021 IBC factors:

Virginia footnote f states that the occupant load for pools follows the "Skating rinks, swimming pools" category of IBC Table 1004.5.

Step 2: selected Table 403.1 ratios

Footnote e: business and mercantile occupancies with an occupant load of 15 or fewer do not need a service sink. Virginia added footnote g, which gives separate ratios for multi-user gender-neutral toilet facilities in several assembly rows. Virginia also added an airport terminal row and a marina table (403.1.4). Under 403.1.4, separate facilities are not required where a marina has fewer than 25 slips, and urinals may replace up to 50% of the water closets.

Step 3: calculation rules (IPC 403.1.1 to 403.1.3)

1. Divide the total occupant load in half to get the occupant load of each sex.
2. Apply the ratio to each sex separately.
3. Round fractions up to the next whole number. For multiple occupancies, add the fractions for each occupancy first and then round up.
4. Exceptions: the load does not have to be split in half where approved statistical data show a different distribution. Under Virginia's exception 2, multi-user facilities designed for all genders are calculated on 100% of the total occupant load. Under Virginia's exception 3, the load need not be split where single-user water closets and bathing fixtures are provided under 403.1.2.
5. 403.1.2: fixtures in single-user toilet and bathing rooms, including family or assisted-use rooms, count toward the required total and must be identified as available to all persons regardless of sex.
6. 403.1.3: where two or more toilet rooms are provided for each sex, distribute the required lavatories in proportion to the water closets.
7. 419.1: every 20 inches of rim space on a group wash fixture counts as one lavatory.

Worked example: 45,000 sq ft office (Group B)

• Occupant load: 45,000 ÷ 150 = 300, so 150 male and 150 female.
• Water closets per sex: first 50 ÷ 25 = 2, plus remaining 100 ÷ 50 = 2, so 4 per sex.
• Lavatories per sex: first 80 ÷ 40 = 2, plus remaining 70 ÷ 80 = 0.875, for 2.875, rounded up to 3 per sex.
• Drinking fountains: 300 ÷ 100 = 3. Under 410.4, because three or more are required, water dispensers may replace up to 50% of them.
• Service sinks: 1.
• Urinals: in a business occupancy, up to 50% of the male water closets, so at most 2 of the 4 male water closets may be urinals (424.2).

Separate facilities (IPC 403.2, as amended)

Separate facilities for each sex are required, except:

1. In dwelling units and sleeping units.
2. In structures or tenant spaces with a total occupant load of 15 or fewer, counting employees and customers.
3. In mercantile occupancies with a maximum occupant load of 100 or fewer.
4. In business occupancies with a maximum occupant load of 25 or fewer.
5. Where single-user toilet rooms are provided under 403.1.2 (they need not be designated by sex).
6. Virginia: where multi-user gender-neutral facilities comply with 405.3 and VCC 1109.2.6.

403.2.1: where each required separate facility would have only one water closet, two family or assisted-use toilet rooms may serve as the separate facilities.

Location and access (IPC 403.3 to 403.6)

• 403.3: public toilet facilities are required for customers, patrons and visitors, and employees must be provided with facilities. They are not required for parking garages without attendants, or for quick-transaction spaces (takeout, pickup, drop-off) with a public area of 300 sq ft or less.
• 403.3.1: the route may not pass through kitchens, storage rooms or closets, and the public must have access whenever the building is occupied.
• 403.3.2: toilet rooms must not open directly into a room used to prepare food for the public.
• 403.3.3 (Virginia): in occupancies other than malls and airport terminals, facilities must be within one story and a 500-foot path of travel. Virginia added an exception for cemetery property.
• 403.3.4 and 403.3.5: in malls and airport terminals, the limit is 300 feet. Airport facilities must be provided both before and after the main security checkpoint.
• 403.3.6 (Virginia renumbering): pay facilities must be in addition to the required free facilities.
• 403.3.7: the egress door of a toilet room used by multiple occupants must not be lockable from inside, except in family or assisted-use rooms.
• 403.4: signs must designate the sex, and directional signs must be visible from the main entrance.
• 403.5: drinking fountains are not required in each tenant space if public fountains are within 500 feet (300 feet in a mall) and one story. 403.6: in malls, service sinks may be within 300 feet.

Urinals and drinking fountains

• 424.2: urinals may replace up to 67% of the required water closets in assembly and educational occupancies and up to 50% in all other occupancies. Virginia's exception for multi-user gender-neutral rooms limits this to 22.5% in assembly and educational occupancies and 25% in all others.
• 410.2: no drinking fountains are required for an occupant load of 15 or fewer.
• 410.3: where fountains are provided, at least two are required: one for wheelchair users and one for standing persons. A single unit with two spouts may serve both.
• 410.4: restaurants that serve free drinking water in a container need no fountain. Elsewhere, where three or more fountains are required, water dispensers may replace up to 50% of them.
• 410.5: drinking fountains, water coolers and water dispensers must not be installed in public restrooms.