Plumbing fixture counts depend on whether your jurisdiction adopted the International Plumbing Code (IPC, used by most states) or the Uniform Plumbing Code (UPC, used by California and a cluster of other jurisdictions, including some cities within otherwise-IPC states). This page does not include a fixture-count calculator, because the specific numeric ratio tables need verification directly against the current ICC (IPC) or IAPMO (UPC) text rather than a secondary paraphrase.
Before you read this: what this page is and is not
This page does not give you a fixture count. It explains why one number cannot cover every project: the applicable table depends on which plumbing code your jurisdiction adopted, and on California’s own occupant-load basis where the UPC applies. No specific fixture-to-occupant ratio appears anywhere on this page, because the ratios were not verified against a primary source for this batch of pages. Confirm the exact numbers for your project with your Authority Having Jurisdiction (AHJ) or a current, direct copy of the adopted code text.
Which plumbing code does your jurisdiction use?
Two model codes cover required plumbing fixture counts in the United States, and which one applies depends entirely on local adoption — not on the building code your project otherwise follows. The International Plumbing Code (IPC) is used by most states. The Uniform Plumbing Code (UPC) is used by California and a cluster of other jurisdictions, including some cities within states that otherwise adopt the IPC. This split is summarized in LADBS Information Bulletin P/BC 2014-095 and a City of Santa Barbara plumbing fixtures bulletin (both fetched and read in full, 2026-09-17).
| Code | Where it is typically used | How fixture requirements are structured |
|---|---|---|
| International Plumbing Code (IPC) | Adopted by most U.S. states | A national base table sets fixture ratios by occupancy classification, generally split by sex, with urinal-substitution and unisex-facility allowances for small occupant counts |
| Uniform Plumbing Code (UPC) | Adopted by California (as the California Plumbing Code) and a cluster of other jurisdictions, including some cities within otherwise-IPC states | California’s own version uses a plumbing-specific occupant-load table, separate from the building code’s egress occupant-load table, then applies its own fixture-ratio structure by occupancy |
Why you cannot reuse an egress occupant load for this
The occupant load you calculate for egress purposes — the one this site’s own occupant load calculator estimates from IBC Table 1004.5 — is a building-code number, built for exit width and exit count. California’s plumbing code (the CPC) uses a separate, plumbing-specific occupant-load table for determining fixture counts, and the two numbers can differ significantly for the same space. Even in an IPC jurisdiction, confirm which occupant-load basis the plumbing fixture table itself calls for rather than assuming the egress number transfers directly.
The general shape of a fixture-count table, without the numbers
Both the IPC and the UPC follow a similar structure, even though their specific ratios differ and were not verified for this page:
- Start from occupancy classification. The building or space’s use — assembly, business, mercantile, educational, and so on — determines which row of the table applies, similar in spirit to how occupant load factors vary by function.
- Fixtures are required per number of persons. The table sets a ratio, such as one fixture per some number of occupants, typically calculated separately by sex where the facility provides separate-sex fixtures.
- Urinal substitution is commonly allowed. Both code families generally permit substituting a limited number of urinals for water closets in men’s facilities, up to a stated proportion.
- Small occupant counts often get a unisex allowance. Below a certain total occupant count, a single unisex facility is commonly permitted instead of separate-sex facilities.
None of the specific numbers behind these rules — the ratio itself, the urinal-substitution proportion, or the unisex threshold — are stated here, because they were not verified against the current primary text for this page.
Why this page has no calculator
This page intentionally does not include a fixture-count calculator. The IPC and UPC fixture-ratio tables are specific, code-edition-dependent numbers, and the research behind this page found only a secondary paraphrase of them, not a figure checked directly against the current ICC (IPC) or IAPMO (UPC) text. Publishing an unverified ratio risked putting an incorrect number in front of someone making a real design decision, so this page describes the structure instead and points to two sources that publish the current tables directly: up.codes, which republishes current code text section by section and is free to browse, and your local building department, which can confirm the adopted code family, edition, and any local amendments for your specific project.
Where Groundbook fits
Groundbook’s document review already checks fixture schedules against the tags printed on the plans as part of its schedules-and-tags check: every plumbing fixture tag should resolve to one schedule row that agrees with the plan on type and quantity — see how Groundbook reads a whole blueprint set. That check confirms a plan and its own schedule agree with each other; it does not calculate how many fixtures the applicable code requires in the first place, which is the question this page addresses.