Electric Water Heater

[smayhan2 (Shane Mayhan, TREC 22021)]

Can anyone tell me where in the IRC it states that an electric water heater must be elevated 18" in a garage?

[jfunderburk (Joe Funderburk, CMI)]

It doesn’t. “Ignition source” must be elevated 18".

[cevans (Chuck Evans, CMI)]

The ignition source must be 18 inches above the floor. When you read the definition for ignition source it becomes clear that the contacts in the electric water heater are a source of ignition.

Per IRC R202

IGNITION SOURCE. A flame, spark or hot surface capable
of igniting flammable vapors or fumes. Such sources include
appliance burners, burner ignitions and electrical switching
devices.

For my home installation, I needed to raise the unit about 8 inches to get the ignition source above 18 inches.

M1307.3 Elevation of ignition source. Appliances having an
ignition source shall be elevated such that the source of ignition
is not less than 18 inches (457 mm) above the floor in garages.
For the purpose of this section, rooms or spaces that are not part
of the living space of a dwelling unit and that communicate
with a private garage through openings shall be considered to
be part of the garage.

For gas appliances

G2408.2 (305.3) Elevation of ignition source. Equipment and
appliances having an ignition source shall be elevated such that
the source of ignition is not less than 18 inches (457 mm) above
the floor in hazardous locations and public garages, private
garages, repair garages, motor fuel-dispensing facilities and
parking garages. For the purpose of this section, rooms or
spaces that are not part of the living space of a dwelling unit and
that communicate directly with a private garage through openings
shall be considered to be part of the private garage.

Water heater specific, regardless of fuel

P2801.6 Water heaters installed in garages. Water heaters
having an ignition source shall be elevated such that the source
of ignition is not less than 18 inches (457 mm) above the garage
floor.

[smayhan2 (Shane Mayhan, TREC 22021)]

Thank you, would you have the reference?

[smayhan2 (Shane Mayhan, TREC 22021)]

That answered my question, thank you for your help.