IPC 604.4, UPC 401.3 and IRC P2903.2 as amended by Phoenix: What flow rates are fixtures allowed?

Phoenix adopted these changes with the rest of the 2024 codes under Ordinance G-7397, effective August 1, 2025. The IPC amendment splits Section 604.4 into two tables. Most buildings use Table 604.4(1). The exception text says exceptions 1 through 5 (blowout toilets up to 3 1/2 gallons, vegetable sprays, clinical sinks up to 4 1/2 gallons, service sinks and emergency showers) are not required to comply with either table, and "Situations meeting exceptions 6 through 12 shall comply with Table 604.4(2)."

The UPC amendment carries the same split through Sections 401.3, 407.2.1, 408.3, 411.2, 412.1 and 420.2, with one difference: where exceptions 6 through 12 apply, UPC 408.3.1 lets showerheads and body sprays run up to 2.5 gpm at 80 psi.

The IRC amendment, for one- and two-family homes, has one table and no exceptions: lavatory faucets 1.5 gpm, shower heads 2.0 gpm, sink faucets 1.5 gpm and toilets 1.28 gallons per flushing cycle. It adds that "A hand-held shower shall be considered to be a shower head."

Exceptions 6 through 12, in the city's words, cover:

• A building that "does not have a demand recirculation water system and includes one or more centralized potable water-heater systems serving two or more dwelling units or sleeping units."
• A building more than six stories above grade plane or more than ten stories.
• A building larger than 50,000 square feet with one or more potable water booster pumps.
• A facility where 5 or more people, excluding staff, receive custodial or medical care on a 24-hour basis.
• Buildings with surgery areas, or areas housing or treating people for burns, chemotherapy or organ or bone marrow transplants.
• Areas housing or treating people who are immunocompromised, on immune-suppressing drugs, or have renal disease, diabetes or chronic lung disease.
• Spaces whose primary purpose is housing occupants under 2 or over 65.

The UPC justification explains the reason: some situations "could potentially be at higher risk of waterborne pathogens," and "Higher flow rates help move this water through the system faster."

• gpm and gpf: gallons per minute for faucets and showers; gallons per flush (or flushing cycle) for toilets and urinals.
• Demand recirculation system: a hot water loop pump that runs on demand to bring hot water to fixtures. A central water heater serving several units without one is exception 6.
• Grade plane: the reference ground level used to count stories.
• Metering faucet: a self-closing faucet that delivers a set amount per push.

New and relocated fixtures installed under a Phoenix plumbing permit, in homes (IRC or the plumbing code the plans use) and in commercial buildings (IPC or UPC). Phoenix's Section 101.4.3 says the UPC or the IPC, as amended, applies to plumbing installations, so the code the plans follow decides which wording applies.

This does not apply to fixtures already in place. And the city's permit exemption in Section 105.2 for replacing toilets, valves or fixtures is limited to "new valves or fixtures complying with the water conservation requirements of this Code," so a swap still has to meet these limits.

• A homeowner swaps an old 3.5-gallon toilet in the same spot. Section 105.2 says "Permits shall not be required for the following," and lists replacing water closets with fixtures "complying with the water conservation requirements of this Code." So the exemption only works if the new toilet meets 1.28 gallons per flush, and moving it needs a permit.
• A developer designs a 4-story apartment building with a central boiler. If it has no demand recirculation system, exception 6 applies and the fixtures follow the higher table. Add a demand recirculation loop and the answer flips back to Table 604.4(1).
• A senior living community. Exception 12 covers spaces whose primary purpose is housing people over 65, so 1.6-gallon toilets and 2.2 gpm faucets are allowed there.

1. 1Confirm which code the plans use: IRC for a house, or UPC or IPC for other buildings.
2. 2Walk the seven exceptions against the building before you pick fixtures.
3. 3Put the ratings on the plumbing sheets. The city's Commercial Building Permit Submittal Checklist lists, under "Plumbing Plan," "Plumbing fixture specifications," a "Plumbing fixture connection schedule" and a "Minimum plumbing fixture analysis." Put each fixture's gpm or gpf rating next to those entries; the checklist does not prescribe a ratings column.
4. 4File through Phoenix Planning & Development (PDD). The checklist asks for owner or applicant information (name, address, phone and a contact person who is the owner or the owner's representative) and for contractor information (name, address, phone, license number and state privilege tax number), which it says is "Required for most projects by Arizona State Law." Commercial and multifamily plan review and permits are in the SHAPE PHX portal, which PDD says opened for them on April 27, 2026. House plans go through the portal's residential applications. The checklist gives PDD's address as 200 West Washington Street, 2nd Floor, Phoenix, AZ 85003, and (602) 262-7811 for questions.
5. 5Buy fixtures rated at or below the limit for the table that applies.
6. 6Keep the fixture spec sheets on site through the final inspection.

• "1.6-gallon toilets are still the standard." In Phoenix, 1.6 is now only for buildings meeting exceptions 6 through 12; everywhere else it's 1.28.
• "The UPC and IPC limits match exactly." They match for most buildings, but under the exceptions the UPC allows showerheads up to 2.5 gpm while IPC Table 604.4(2) stays at 2.0.
• "Replacement fixtures don't have to comply." The permit exemption itself requires replacements that comply with the code's water conservation requirements.