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Building Code Reference

Got a CALGreen 4.303 correction?

Water-conserving fixtures

For builders in California, Greater Seattle, the Las Vegas area, the Denver area and Kansas City · CrossBeam Permits

What this code requires, how to fix it, and how cities and counties review it

What this code requires

CALGreen 4.303 requires every new residential building in California to install water-conserving plumbing fixtures that meet maximum flow and flush rates set by state code. Toilets must not exceed 1.28 gallons per flush (GPF). Kitchen faucets must not exceed 1.8 gallons per minute (GPM). Lavatory faucets must not exceed 1.2 GPM. Showerheads must not exceed 1.8 GPM. These limits apply to new construction and additions covered under the California Green Building Standards Code. Single-family, multifamily, and ADU projects all hit this section.

How to fix it

  1. Add a plumbing fixture schedule with flow rates

    Your plumbing plans need a fixture schedule that lists each fixture type, the manufacturer/model (or spec equivalent), and the rated GPF or GPM. Add a column for each fixture row: toilets show GPF, faucets and showerheads show GPM. The plan-checker will compare these numbers against CalGreen 4.303 limits during review. A note that says 'all fixtures shall comply with CalGreen 4.303' without numbers does not satisfy the requirement — you need the actual rated values on the schedule.

  2. Verify toilet specs at 1.28 GPF or less

    Standard toilets are 1.6 GPF. High-efficiency toilets (HETs) are 1.28 GPF. CalGreen 4.303 requires 1.28 GPF or less. Pull the spec sheet for the toilet model you're installing and confirm the flush volume. For dual-flush toilets the limit applies to the effective flush volume, the average of two reduced flushes and one full flush, which must be 1.28 GPF or less. If you're using a 1.6 GPF toilet anywhere on the project, swap it or the plans won't pass. Note the model number and GPF rating in the fixture schedule.

  3. Verify kitchen faucet at 1.8 GPM or less

    Kitchen faucets at 2.2 GPM are still widely available and are on the shelves at most supply houses. They don't pass CalGreen 4.303. Confirm your kitchen faucet spec sheet shows 1.8 GPM or less at 60 psi. Many WaterSense-labeled kitchen faucets are at 1.5 GPM, which passes. Note the rated GPM in the fixture schedule next to the kitchen sink fixture entry.

  4. Verify lavatory faucets at 1.2 GPM or less

    This is the one that catches contractors most often. The limit for lavatory (bathroom) faucets is 1.2 GPM, not 1.5 GPM, not 1.8 GPM. A lot of WaterSense faucets are rated 1.5 GPM, which passes for kitchen but fails for lavatory under CalGreen 4.303. Pull the spec sheet for each bathroom faucet model. If the flow rate is above 1.2 GPM, you need a different model. Note the rated GPM for each lavatory faucet in the fixture schedule.

  5. Verify showerheads at 1.8 GPM or less

    The CalGreen 4.303 limit for showerheads is 1.8 GPM at 80 psi. Many standard showerheads are 2.0 or 2.5 GPM — these fail. Check the spec sheet for the shower fixture you're installing. The flow rate must be tested at 80 psi per CEC/ASME standards, so confirm the spec sheet cites the correct test pressure. If you're installing a multi-spray or rain-style showerhead, the combined flow of all showerheads and other outlets on a single valve must not exceed 1.8 GPM at 80 psi, or the shower must allow only one outlet to run at a time. Note the showerhead model and GPM in the fixture schedule.

  6. Cross-check plans against spec sheets before resubmitting

    After updating the fixture schedule, go through the plan set and flag every place a fixture is called out. Make sure the GPF/GPM noted on the schedule matches the spec sheet in your submittal package. Inconsistencies between the plans and the cut sheets are a second-round correction waiting to happen. If you're pulling spec sheets from a manufacturer website, print or save the page showing the flow rate — attach it to your resubmittal package so the plan-checker doesn't have to hunt for it.

  7. Confirm system pressure won't push flow rates over the limit

    CalGreen fixture limits are tested at specific pressures: 80 psi for showerheads, 60 psi for faucets. If your building's static pressure is significantly higher than the test pressure, the actual delivered flow at the fixture can exceed the rated value. If the system pressure at the fixture will be above the test pressure, add a pressure-reducing valve (PRV) or confirm that the aerators and flow restrictors are rated for the actual operating pressure. This comes up on high-pressure sites and is worth a quick check before resubmitting.

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Why you got flagged

Here's why plan-checkers flag CALGreen 4.303: the most common trigger is that the plumbing plans don't call out fixture flow rates at all. The plan-checker has no way to confirm compliance without seeing GPF and GPM specs noted on the plumbing schedule or fixture schedule. If your plans just say "low-flow toilet" or "water-saving faucet" with no numbers, that's a correction.

A second common scenario is a mismatch between the spec sheet and the code limit. A contractor sources a showerhead rated at 2.0 GPM, which used to be standard, and the plan-checker catches it because the current CalGreen limit is 1.8 GPM. Same issue with kitchen faucets: 2.2 GPM aerators are still common on job sites and at supply houses, but they don't meet the 1.8 GPM cap.

Lavatory faucets are the one that trips people up most often. The 1.2 GPM limit for lavatories is tighter than most people expect. A lot of contractors spec 1.5 GPM faucets thinking they're "low-flow" and they're right that 1.5 GPM is low-flow by older standards, but it doesn't pass CalGreen 4.303. If your lavatory faucet specs read 1.5 GPM anywhere on the plans, you'll get flagged.

Bathroom faucets and kitchen faucets get lumped together in contractor shorthand, but they have different limits under 4.303: lavatory is 1.2 GPM, kitchen is 1.8 GPM. Mixing these up on the fixture schedule — or applying the kitchen limit to lavatories — is a pattern that shows up in corrections letters regularly.

The official code

California Green Building Standards Code (CALGreen) — Title 24 Part 11, Section 4.303

Read the source →

Common questions

Does CALGreen 4.303 apply to ADU additions?
Yes. CALGreen mandatory measures apply to newly constructed ADUs and to additions that include new plumbing fixtures. If you're building a new detached ADU or converting a garage into an ADU with a bathroom or kitchen, all new fixtures must meet the 4.303 flow rate limits. Existing fixtures that are not being disturbed by the permitted scope of work are generally exempt. But anything you're adding or replacing under the permit needs to comply. If you're doing a partial bathroom remodel and only replacing the vanity faucet, that faucet needs to be 1.2 GPM or less.
What is the toilet GPF limit under CalGreen 4.303?
The limit is 1.28 GPF. Standard toilets are 1.6 GPF and fail CalGreen 4.303. You need a high-efficiency toilet (HET) rated at 1.28 GPF or less. Dual-flush models are judged on effective flush volume, the average of two reduced flushes and one full flush, which must be 1.28 GPF or less. WaterSense-labeled toilets are 1.28 GPF by definition, so any WaterSense toilet passes this check. Confirm the spec sheet shows the rated flush volume, not just the WaterSense label, since the plan-checker will want to see the number.
Can I use a 1.5 GPM aerator on a bathroom faucet?
No. The CalGreen 4.303 limit for lavatory (bathroom) faucets is 1.2 GPM. A 1.5 GPM aerator exceeds that limit and will get flagged. For kitchen faucets, 1.5 GPM is fine since the kitchen limit is 1.8 GPM. The distinction matters: lavatory and kitchen faucets have different caps under this section. If you buy a WaterSense-labeled faucet rated at 1.5 GPM, it will pass the kitchen check but fail the lavatory check. Check the specific GPM on the spec sheet and match it to the correct fixture type.
Does a 2.0 GPM showerhead pass CalGreen 4.303?
No. The CalGreen 4.303 showerhead limit is 1.8 GPM tested at 80 psi. A 2.0 GPM showerhead exceeds the limit and will trigger a correction. This is one of the most common CalGreen fixture errors because 2.0 GPM showerheads are still widely sold and contractors sometimes assume 'low-flow' covers anything under 2.5 GPM. Under CalGreen, the hard limit is 1.8 GPM. If you've already spec'd a 2.0 GPM fixture, swap it before resubmitting — the plan-checker will catch it again on round two.
Do CalGreen fixture requirements apply to remodels?
It depends on scope. CalGreen 4.303 applies to new construction and to the scope of permitted additions or alterations. For remodels, it applies to any new fixture being installed as part of the permitted work. If your permit covers a bathroom remodel that includes replacing the toilet and faucets, the new fixtures must meet 4.303 limits. Fixtures that are not being touched in the permitted scope are generally not subject to upgrade requirements. When in doubt, read the permit scope description carefully — anything listed there is subject to CalGreen mandatory measures.
What are all the CalGreen 4.303 flow rate limits?
The current CalGreen 4.303 maximums are: toilets at 1.28 GPF; kitchen faucets at 1.8 GPM; lavatory (bathroom) faucets at 1.2 GPM; showerheads at 1.8 GPM. Urinals (where installed in residential settings) max out at 0.125 GPF. These apply to the current adopted edition of CALGreen. California's triennial code adoption cycle can update these numbers, so if you're working on a project permitted under an older edition, confirm which edition governs your permit. The permit date and the jurisdiction's adoption date determine which edition applies.

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