Because a gas water heater is defined as a “fuel-fired” appliance by the International Residential Code (IRC) and the Residential Edition of the Florida Building Code (FBC M2005.2), there are life-safety concerns relating to making sure that combustion gases are exhausted outside the living area, providing adequate air for combustion without depleting the oxygen in the living area of the home, and preventing the water heater from igniting a house fire.

Where A Gas Water Heater Cannot Be Installed

• A gas water heater must not be installed in a room used as a storage closet. This also means that a dedicated water heater closet should not later have stuff stored in it.

Where a Gas Water Heater Can Be Installed, But With Limitations 

• Water heaters cannot be installed in a bedroom or bathroom unless in a sealed enclosure (closet) that has combustion provided from outside the living area. Direct-vent water heaters are exempt from the enclosure requirement because they are a sealed system specifically designed to use outdoor air for combustion.

• Gas water heaters installed in an attic or underfloor crawl space are permitted to have access through a closet in a sleeping room (bedroom) or bathroom as long as ventilation of those spaces is in accordance with the building code.

• A gas tank water heater cannot be located in the garage unless it is Flammable Vapor Ignition Resistant (FVIR) or elevated 18-inches off the floor, to protect against igniting any gasoline fumes that might collect near the floor of the garage (FBC P2801.6). All new water heaters are FVIR rated. Also, if the gas water heater is located in the path of a car entering the garage, a stanchion or roll-stop must installed in front of the water heater to protect the gas line from unintentional impact.

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

• Are water heaters required to be raised off the floor? 

• 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?  

• 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? 

• Does a tankless gas water heater still work with no electricity during a power outage?  

•  Why do water heaters have a sacrificial anode? 

• What is the difference between a manufactured/mobile home water heater and a regular water heater? 

• Does a tankless water heater require a pressure relief valve?

• When is a water heater drain pan required?

• 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?

• 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?

• Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises? 

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

• How can I determine the age of a water heater if the serial number is missing or decoding it is impossible? 

• How does a hydronic heating system work?

• 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.