Confirm the permit uses the 2025 California Plumbing Code, Title 24 Part 5, effective January 1, 2026 and adopted from the 2024 Uniform Plumbing Code, and that the plumbing notes do not cite the IPC or the 2022 CPC. Then check the fixture count and restroom design against the architectural plans, including any all-gender multi-user restrooms, trace water conservation and CALGreen fixture data through the schedules, and confirm cross-connection and health care water system details follow the agency rules that apply. AI can flag conflicts; the plumbing engineer and the authority having jurisdiction decide compliance.
What does the California Plumbing Code cover?
The California Plumbing Code is Part 5 of the California Building Standards Code, Title 24. The commission-issued errata packet’s history note describes adopting the 2024 Uniform Plumbing Code to become the 2025 CPC and repealing the 2021 edition. Its adopting agencies include the Building Standards Commission, the Division of the State Architect structural safety program, the Department of Water Resources, HCD, OSHPD, and the State Fire Marshal. Changes discussed in the cycle include water consumption, all-gender multi-user restrooms, OSHPD health care water systems, and the Department of Water Resources references in Chapter 15.
The California Building Standards Commission states that the 2025 Title 24 was published July 1, 2025 with an effective date of January 1, 2026, and lists Part 5 in the 2025 edition. Its 2024 triennial cycle page says the cycle adopts the 2024 editions of the ICC and IAPMO model codes and the 2023 edition of the NEC. The CPC errata packet carries the adoption history note, and the commission’s final statement of reasons cites the 2024 UPC. Checked October 19, 2026. The code in effect when the permit application is submitted is the one that applies, cities and counties may adopt local amendments with findings filed with the commission, and the commission’s 2025 intervening cycle will publish supplements effective July 1, 2027.
Model code checks are in the UPC guide, and the plumbing fixture count guide explains how occupant load drives fixtures. Water conservation interacts with CALGreen, which sets its own fixture flow requirements.
Gather the plumbing set and the occupancy data
Collect the plumbing general notes and code references, the fixture count calculation, plumbing floor plans, risers and isometrics, fixture and equipment schedules, the water heater and recirculation drawings, backflow and cross-connection details, recycled or alternate water drawings if present, the plumbing specifications, and the CALGreen checklist. Add the architectural restroom plans and the occupant load from the code analysis.
For health care work, add the domestic water system narrative and any water management documents the agency asks for.
Trace CPC decisions through the plumbing set
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Model code and edition | Plumbing general notes, specifications, cover sheet | Confirm the 2025 CPC is cited and that no sheet relies on the IPC, the 2021 UPC, or the 2022 CPC. |
| Fixture count and restrooms | Fixture count calculation, code analysis occupant load, architectural restroom plans | Check the occupant load and fixture count match the architectural plans, including all-gender multi-user restrooms if the project uses them. |
| Water conservation | Fixture schedule, CALGreen checklist, specifications | Match fixture flow and flush data in the schedule to the CALGreen checklist and the specified products. |
| Cross-connection and alternate water | Backflow details, recycled water drawings, site utility plan | Confirm backflow devices and separation are drawn where alternate or recycled water and potable systems meet. |
| Health care water systems | Domestic water risers, water heater schedule, narrative | Record which OSHPD provisions apply and whether the risers and equipment reflect them. |
| Agency with jurisdiction | Code analysis, cover sheet | Record which agency’s amendments apply to the building or area. |
Fixture products continue in the plumbing fixture specifications guide, layout checks in the plumbing drawing checklist, and the building code side in the California Building Code guide.
Example: restroom counts that changed with the floor plan
Hypothetical example. A restaurant tenant improvement in Oakland revised its seating layout late in design. The architectural plans now show one all-gender multi-user restroom in place of two single-user rooms, the plumbing fixture count calculation still uses the earlier occupant load, and the fixture schedule lists lavatory faucets whose flow rate differs from the CALGreen checklist.
The architectural plans show an all-gender multi-user restroom replacing two single-user rooms, but the fixture count uses the earlier occupant load and the fixture schedule’s faucet data differs from the CALGreen checklist. Confirm the occupant load, restroom design, and fixture data, and coordinate the plumbing and architectural sheets.
The plumbing engineer updates the count and schedule with the architect. The finding is a document conflict; the building official decides fixture requirements.
Review California plumbing drawings with Groundbook
Upload the current drawings and specifications to Groundbook, and state the edition, amendments, and review scope in your instructions. Add the California Plumbing Code edition the project uses from a copy you are licensed to use, where the license permits uploading it, and the jurisdiction’s published amendments. See how Groundbook works with local and licensed codes.
Compare the plumbing general notes, fixture count calculation, code analysis occupant load, architectural restroom plans, plumbing plans, risers, fixture and equipment schedules, backflow and alternate water details, CALGreen checklist, and plumbing specifications. Flag a cited IPC, 2021 UPC, or 2022 CPC instead of the 2025 CPC, fixture counts that do not match the occupant load or restroom plans, fixture data that differs from CALGreen, missing backflow protection between water systems, and no stated agency with jurisdiction. Use the supplied CPC and cite both sources.
Groundbook links each potential finding to the sheets and documents involved. It does not size piping or calculate fixture units.
Document review does not certify compliance or approve a permit. Those remain with the plumbing engineer and the authority having jurisdiction.