Skip to content
CrossBeamStart a pre-check

Building Code Reference

Got a CPC 408.4 correction?

Shower and tub-shower control valves

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

CPC 408.4 requires every shower and tub-shower in California to have an individual control valve of the pressure-balance, thermostatic, or combination type, listed to ASSE 1016/ASME A112.1016/CSA B125.16 and installed at the point of use. The valve has to provide scald and thermal shock protection for the rated flow of the installed showerhead, and CPC 408.4.2 limits the water leaving the showerhead to 120°F. Any permit involving a new or relocated shower or tub-shower in a residential or commercial project triggers a plan-check review under this section.

How to fix it

  1. Confirm the valve type on the plumbing fixture schedule

    Open your plumbing fixture schedule and find the shower or tub-shower valve entry. The valve must be explicitly identified as a pressure-balance, thermostatic, or combination type listed to ASSE 1016/ASME A112.1016/CSA B125.16. A plain "shower valve" or "volume control" entry will not pass. Update the schedule to include the manufacturer name, model number, and the ASSE standard it meets. If you are using a combination cartridge (pressure-balancing plus volume control in one body), confirm the cartridge itself carries the ASSE 1016 listing, not just the trim kit.

  2. Add the 120°F maximum outlet temperature note

    On the plumbing plan sheet (or in the fixture schedule), add a clear note stating the anti-scald valve is set to limit outlet temperature to a maximum of 120°F per CPC 408.4.2. Plan-checkers are trained to look for this language. The temperature limit applies to every shower and tub-shower on the project, so if you have multiple fixtures, either list the note on each or add it as a general plumbing note on the cover sheet with a pointer to all affected fixtures.

  3. Attach the valve spec sheet to the submittal

    Pull the manufacturer cut sheet for the valve and attach it to the plan set as a reference sheet. The cut sheet must show the ASSE listing number clearly. Popular choices like the Moen Posi-Temp, Delta Monitor, and Kohler Rite-Temp cartridges are all ASSE 1016-listed and widely accepted across California jurisdictions. If your valve is thermostatic (common on European-style fixtures or high-end hotel builds), confirm it carries the ASSE 1016 listing and that the spec sheet states the adjustable maximum temperature stop. Stamp or label the reference sheet with "CPC 408.4 Compliance" so the reviewer finds it without digging.

  4. Flag retained existing valves with the model number and listing

    On a remodel where the existing valve stays, do not just write "existing valve to remain." Add the existing valve manufacturer and model number to the plans, then note the ASSE listing. If the existing valve predates ASSE 1016 listing requirements or is an older single-handle valve without anti-scald protection, the plan-checker will require replacement. Check the model number on the valve trim or cartridge before finalizing the plans; replacing language after the first correction costs you another review cycle.

  5. Check whether institutional projects require thermostatic valves

    For hotels, care facilities, dormitories, or any project subject to local health-department rules, check whether a thermostatic valve is required rather than a plain pressure-balancing valve. Gang showers on a single tempered supply need an ASSE 1069 mixing valve (CPC 408.4.1). In some California jurisdictions and for certain occupancy types, the pressure-balancing cartridge alone does not satisfy the requirement. If in doubt, spec the thermostatic valve; it meets the pressure-balancing requirement automatically and gives you one less thing to defend at the counter.

  6. Revise the plan sheet and resubmit with a response letter

    After updating the fixture schedule, adding the temperature note, and attaching the spec sheet, prepare a short response letter that maps each correction item to the sheet and detail where you addressed it. A response like "CPC 408.4: Updated fixture schedule Sheet P-1 to specify [manufacturer and model] pressure-balance valve (ASSE 1016). Cut sheet attached as Sheet P-7. Maximum outlet temp note added to General Plumbing Notes." gives the plan-checker exactly what they need to close the item. This reduces the chance of a second correction on the same line.

Take the CPC 408.4 fix steps with you

All 6 steps in one email, so you have them on site instead of on this page.

Why you got flagged

Plan-checkers cite CPC 408.4 when the plumbing plans show a shower or tub-shower without specifying an anti-scald valve. The most common miss is simply listing a shower valve by brand and model number with no note confirming it meets ASSE 1016 (which covers pressure-balance, thermostatic, and combination shower valves). A reviewer cannot approve what they cannot verify, so if the spec sheet is not attached or the note is silent on the standard, they will flag it.

The second common trigger is showing a mixing valve or a volume control valve at a shower without clarifying whether it includes pressure-balancing protection. Volume controls alone do not satisfy CPC 408.4. If the schedule just says "shower valve per architect specification" and that spec sheet is buried elsewhere in the set, the plan-checker will write a correction rather than go hunting for it.

A third scenario hits remodel projects where the existing valve is being retained. If the plans note "existing valve to remain" on a shower that is being reconfigured or retiled, the plan-checker may require verification that the retained valve is a listed pressure-balancing or thermostatic type. Saying "existing valve to remain" without noting the valve model or its ASSE listing is enough to get flagged.

Hotels, assisted-living facilities, and projects with institutional showers also get a harder look. The 120°F maximum applies everywhere, but high-occupancy settings may require a thermostatic mixing valve rather than just pressure-balancing, depending on the applicable code edition and local amendments. If your project is anything other than a basic single-family residential shower, include the valve spec sheet and call out the ASSE 1016 listing explicitly.

The official code

2025 California Plumbing Code Section 408.4 — Individual Shower and Tub-Shower Combination Control Valves

Read the source →

Common questions

Does CPC 408.4 apply to bathtubs that are not showers?
CPC 408.4 applies specifically to showers and tub-showers (a tub with a showerhead). A freestanding soaking tub or a bathtub without a showerhead falls under CPC 409.4 instead, which limits the water from the bathtub filler to 120°F. That limit is met with a limiting device listed to ASSE 1070/ASME A112.1070/CSA B125.70 or CSA B125.3, or with a water heater conforming to ASSE 1084. If your tub has a hand shower or a fixed overhead shower, it qualifies as a tub-shower and the 408.4 valve requirement applies.
Will a standard pressure-balancing valve pass or do I need thermostatic?
A pressure-balancing valve meeting ASSE 1016 satisfies CPC 408.4 for most residential and light commercial projects. Thermostatic valves are not required by the statewide code for a typical single-family shower, but some jurisdictions, occupancy types, or project-specific conditions can change that. If your project is a hotel, care facility, or is subject to accessibility provisions, check with the local building department before assuming pressure-balancing alone is sufficient. When in doubt, spec the thermostatic valve since it satisfies the pressure-balancing requirement automatically.
Can I use an existing shower valve on a remodel if I am just replacing tile?
Potentially, but you have to document it. Simply writing "existing valve to remain" on the plans is not enough. You need to identify the valve by manufacturer and model number and confirm it carries an ASSE 1016 listing. If the valve is old enough that it predates these standards, or if it is an unbranded import without a listing, the plan-checker can require replacement. Pull the valve trim and check the cartridge or valve body for the model number before finalizing your remodel plans. Replacing a note after a correction costs you another full review cycle.
What is the maximum water temperature allowed at a shower under CPC 408.4?
CPC 408.4.2 limits the maximum water temperature discharging from an individual showerhead to 120°F. For an individual shower or tub-shower, you meet that limit with an ASSE 1016 valve that is either field-adjusted to the maximum temperature or has its handle position, stop, or temperature limit control set per the manufacturer's instructions. Note on the plans how the limit will be set, and confirm the method in the spec sheet. If you are on a project where the water heater is set higher (some commercial kitchens run domestic hot water at 140°F for legionella control), the shower valve must still limit the showerhead to 120°F.
Do ADUs need anti-scald valves at the shower under CPC 408.4?
Yes. An ADU is a residential occupancy and CPC 408.4 applies to every shower and tub-shower regardless of whether the unit is attached, detached, or a conversion. ADU corrections letters frequently include a CPC 408.4 item because the plumbing schedule gets treated as boilerplate from the main house plans and the shower valve spec is left vague. Fix it by naming the valve model and ASSE listing in the fixture schedule on the ADU plumbing sheet.
Which ASSE standard covers pressure-balancing shower valves?
CPC 408.4 names ASSE 1016/ASME A112.1016/CSA B125.16 for pressure-balance, thermostatic, and combination valves at individual showers and tub-showers. ASSE 1070 shows up in CPC 409.4 for bathtub filler limiting devices, not as the shower valve standard. For most shower valves in California residential construction, ASSE 1016 is the listing you are looking for. When you call out the valve on your plans, note the ASSE 1016 listing explicitly; do not just say "anti-scald valve" since that phrase by itself does not confirm the listing to a plan-checker.

Related corrections

Check my plans for this →