Yes a gas water heater can be installed in a closet as long as the closet is not used for storage.
Water heater closet door requirements.
No water closet or bidet shall be set closer than fifteen 15 inches 505 0 water heater requirements.
You can do this by attaching a piece of plywood on the back side of the door.
Irc2012 sec r302 5 1 pc1 pcinspector1.
If the gas furnace and or water heater is in a closet between the residence and the garage then the door has to be self closing and solid core.
If the floor of the closet is carpeted you must install a metal plate between the bottom of the water heater and the carpet.
Code expert glenn mathewson describes 10 common water heater code issues including confusion about drip pans and drains unsupported expansion tanks and plastic vents lack of combustion air and more.
The door assembly shall be installed with a threshold and bottom door seal and shall meet the requirements of section 504 1 2.
The international residential code irc specifically bans a storage closet as a location for a gas water heater.
Closets are required to have doors when a water heater is installed in them and these doors cannot be left open.
The doors must open and close easily and freely and must close and latch by.
Combustion air for such installations shall be obtained from the outdoors in accordance with section 506 4.
Once your combustion vents have been installed and the ceiling in the closet has been finished out you will want to close off any vents in the door.
Insufficient clearance need metal door or fireproof door to reduce clearance requirements.
Water heater shall be of the direct vent type.
The metal plate must extend a minimum of 6 inches beyond the water.
The closet shall be for the exclusive use of the water heater.
Installing a tank water heater might seem easy but homeowners who refinish their basements often create a number of code violations with respect to the water heater.
Apparently not applicable is this instance.
Close off vents in door.
Insufficient combustion air need outside air or a full louvered door or a standard door with high and low vents.