The warning label shown above from the side of a water heater tells you the most important thing you need to know about where to install a water heater: “this water heater, as all water heaters, will eventually leak.” So the best place to locate your water heater is where it will do the least damage when it eventually leaks, such as the garage.

    There are also building code requirements to comply with when placing a water heater:

•• If installed in a location where leakage will do damage, a catch and drain to the exterior must be installed under the water heater. According to the International Residential Code (IRC) and Florida Building Code (FBC) at section P2801.5, a drain pan is required for a water heater in any of these areas of a home:

•  Any level above the ground floor,
•  Or in attics or ceiling areas,
•  Or within the habitable space.

The pan must be a corrosion-resistant metal of minimum 24-gauge or other rated material, with sides at least 1-1/2” deep. A drain pan is not required for a water heater in a garage. 

    A drain pipe should be connected to the side of the pan, made of material rated for water supply pipe, which means that PVC is not acceptable. The pipe has to be at least the same diameter as the cold water supply pipe to the water heater, and it must terminate outside within 6” to 24” of the ground or into an indirect waste receptor.

    The pan is required to have a drain to the exterior, but an exception is allowed at FBC-P2801.6.1: “where a pan drain was not previously installed, a pan drain shall not be required for a replacement water heater installation."

•• A 24” wide by 30” deep space is required in front of a gas water heater for service (IRC M1305.1.2), and 30” wide by 36” deep space necessary in front of an electric water heater [NEC 110.26(A)].

•• A gas water heater cannot be installed in a storage closet (IRC M2005.2) and, of course, a dedicated gas water heater closet cannot later be used for storage.

•• 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 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 have been FVIR rated since 2002. 

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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? 

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

• Where are gas water heaters not allowed to be installed?  

• 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? 

• 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?

• 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 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 is the difference between a regular water heater and a direct vent water heater? 

• What is the difference between a regular water heater and a power vent water heater?

• What is backdrafting at a gas water heater? 

• 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.