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Water Heater Installation Codes in California

Fact checked by Stephen Conklin

water heater installation codes in california

Water heater installation codes in California are some of the strictest in the country. California water heater regulations are unsurprising, given the state’s earthquake-proneness and stringent environmental laws.

If you’re relocating to the Golden State and wish to install a water heater in the home, here are the code requirements you must know.

Table of Contents

Code Requirements for Water Heater Installation in California

The CA water heater code has ten sections covering general information about venting requirements. We recommend reading the California code for water heaters in its entirety to ensure compliance.

1. Water Heater Specifications


Californians must comply with the following California Code for water heaters.

  • Water heaters must have a First-Hour Rating of 42 to 80 gallons, depending on the number of bathrooms.
  • Water heaters must have the correct certifications.
    • Electric water heaters for homes – UL 174
    • Commercial electric water heaters – UL 1453
    • Gas water heaters with maximum 75000 BTU/hour – CSA Z21.10.1
    • Gas water heaters with more than 75000 BTU/hour – CSA Z21.10.3

2. Permits

Do you need a permit to replace a water heater in California? Yes, you do. You need to apply for a water heater permit before installing, replacing, or removing a water heater or hiring someone to do these activities.

Failure to obtain the necessary authority might result in penalties or other legal action. You can check the permit requirements in your local California locality.

  • Water Heater Location


It’s okay to install a gas water heater in a bedroom or bathroom closet, provided the storage space has a listed self-closing device and door assembly. The water heater must only be a direct vent type.

  • Water Heater Vents


California’s water heater code allows you to install non-direct vent types, provided the water heater is close to a gas vent or chimney.

Indoor combustion air should be at least 50 cubic feet for every 1000 BTUs per hour. For instance, you need 2,500 cubic feet of combustion air for a 50,000 BTU water heater.

  •  Water Heater Clearance


Unlisted water heaters must have at least 12 inches of clearance at the rear and sides. Although listed devices don’t have minimum clearances, their location must allow for servicing access and adequate combustion air.

  • Seismic Protection

Although only two to three earthquakes rock the Golden State annually, homeowners must still protect themselves against tremor-related water heater incidents.

California requires its residents to secure their water heaters by strapping or anchoring the devices to sturdy structures. The straps should be at the water heater’s upper and lower one-third. Moreover, the anchoring panels must be at least four inches above the water heater controls.

Other Water Heater Requirements


The following water heater building codes apply to water heaters in California.

  • All water heaters must have pressure-limiting technologies or overpressure protection.
  • All water heaters must have overtemperature protection.
  • Water heaters in California must have vacuum, pressure, and temperature relief mechanisms.
  • A water pressure regulator is a must for all storage tank types.
  • Expansion tanks are necessary to prevent leaks and pressure spikes.
  • A water shutoff valve is essential for safety, especially when there’s no hot water, maintenance requirements, or leaks.
  • Storage tank-type water heaters must have load-distributing bases or platforms.
  • Water heaters in the attic or similar spaces where water damage might occur require a corrosion-resistant watertight pan at least 1.5 inches in depth.

Electric Water Heaters


It’s worth noting that California will be phasing out gas-fueled devices (including water heaters) by 2030 to reduce the Golden State’s carbon footprint. Hence, you might consider installing an electric water heater instead of a gas option.

  • Electric storage tank-type water heaters must have a Uniform Energy Factor (UEF) rating of at least 0.96 or 96%, while tankless versions must have a UEF of at least 0.93 or 93%.
  • Electric storage water heaters must not exceed 0.3 + 27/measured volume % per hour of standby heat loss.

Tankless Water Heaters


California has different regulations for a tankless water heater, although you still need a permit.

  • You cannot install gas-powered tankless heaters in sleeping areas, bathrooms, clothes closets, and confined spaces connecting to a bedroom or bathroom.
  • Tankless gas water heaters must draw combustion air from the outdoors only.
  • Electric versions must have 110.120-volt receptacles within three feet.
  • The first five feet of water line from the water heater must have adequate insulation.
  • You cannot install tankless units in spaces where water heater-related water damage might occur unless you install a listed safety pain with at least a ¾-inch drain.
  • Combustion air vents must be clear of obstructions at least a foot from the top, sides, and bottom.


Water heater installation codes in California exist for your protection, allowing you to design and set up safe and functional water heating systems in your home or establishment.

Although some provisions are similar to the rest of the country, California’s earthquake strapping requirement is a novelty. It isn’t entirely surprising, given the state’s proneness to tremors. The state’s move toward green solutions might see gas-powered water heaters obsolete by 2030.

Now that’s something worth considering.

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