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Are water heaters required to be raised off the floor?

Thursday, June 14, 2018

Only older gas water heaters located in a garage are required by the International Residential Code (IRC) and Florida Building Code (FBC M1307.3) to be elevated. It is not necessary for electric water heaters, or 30 to 50-gallon gas water heaters manufactured after mid-2003. 

    The code states that “appliances having an ignition source shall be elevated not less than 18 inches (457 mm) above the floor in garages,” and the purpose of this stipulation is fire safety. Any gasoline leaking from a car parked in the garage creates flammable fumes that are heavier than air and settle near the floor. An open flame close to the floor, like the pilot light in a water heater, can set off an explosion and subsequent house fire.

FVIR Water Heaters Exempted

    But, even with the requirement to elevate any source of ignition up above the floor, numerous house fires continued to be attributed to the gasoline fume ignition in the garage. So the Consumer Products Safety Commission (CPSC) mandated that all 30, 40, and 50 gallon gas-fired water heaters manufactured after July 1, 2003, have Flammable Vapor Ignition Resistant (FVIR) technology. 

    This makes elevation of the water heater unnecessary, and the code exempts FVIR water heaters from being elevated like the one on the plywood platform in the photo at the top of this page. The code states that “elevation of the ignition source is not required for appliances that are listed as flammable-vapor-ignition-resistant.” There are, however, some jurisdictions that still require even an FVIR water heater to be elevated off the floor, so you should check with your local building department.

   The owner’s manual and/or data plate on the side of a newer water heater will state that it is Flammable Vapor Ignition Resistant, so you can verify if yours has this safety feature. If you can remove a cover plate at the base of the water heater and see a pilot light and burner, then you have an older water heater that is not FVIR. See our blog post What is an FVIR water heater? to learn more.

     But there are a couple of reasons why you may want to elevate your water heater anyway:
•• An elevated water heater is easier to fully drain by gravity to flush the sediment accumulation out of faucet at the bottom. Several years of sediment buildup is what causes a gurgling or rumbling sound each time the water heater starts a heating cycle. See our article Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises? for more on this.
•• When the water heater sits directly on a concrete floor, the moisture in concrete will lead to earlier corrosion of the base.

• • • • • • • • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection of more blog posts about WATER HEATERS: 

Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?

Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code?

Can you use a light switch for a water heater disconnect? 

How can I tell if a water heater is HUD-approved for mobile/manufactured homes?

Can you wire a 240-volt water heater with 120 volts? 

Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?  

What is the minimum clearance to doors and windows for an outdoor tankless gas water heater? 

What is required clearance for access and working space in front of an electric water heater? 

Why is the water heater older than the house? 

Does a water heater need a shut-off valve? 

Why should a tankless water heater have an isolator/service valve kit installed?

When was a gas water heater first required to be elevated 18 inches above a garage floor?  

Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home? 

What is the purpose of a thermostatic mixing valve above a water heater? 

Why is there water in my water heater drain pan?

What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"? 

Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom? 

Where do I find the water heater in a mobile home?

Does a tankless water heater in an attic require a drain pan? 

Does an electric water heater require a disconnect? 

Is a catch pan and drain piping required for a replacement water heater?

What is the difference between a single element and dual element electric water heater? 

What is an FVIR water heater?

What is a heat pump water heater?

What is a dielectric union?

What's that powdery crust on the pipe connections at the water heater? 

What are the most common installation mistakes with water heater replacement? 

What can I do to make my water heater last longer?

How do I determine if a water heater is gas or electric?

What does it mean when a gas appliance (water heater, furnace, or range) has been "red tagged"?  

• What's the valve with the flip-up handle on the water heater for?

• Why is an older water heater an insurance problem?

   Visit our WATER HEATERS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles. 

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