Gas Water Heater Installation

During gas water heater installation, state, local codes and manufacturer instructions must be followed. One of them, for example, is the use of an expansion tank on the incoming water supply in a closed heating system. Some codes also require a special license to connect gas line to your heater, vacuum relief valve, venting regulations and more.


Before installing hot water heater you should carefully choose an indoor location as its placement is very important for safety of the occupants, economical and efficient use of your unit.

Your gas water heater should not be installed in the area where gas or water leakage from the water heating system can damage either adjacent areas or lower floors and cause the damage to the structure.

That is the reason to provide the right drainage solution, under the water heater, like drain line or drain pans. Since the burner and air inlet are located in the lower part of the blower your drainage solution must not restrict this entrance.

Selected location must provide adequate clearance for servicing, maintenance as well. Do not put the tank directly on the carpet, but protect it by using metal or wood panel beneath.

When installing a gas water heater, keep in mind, that combustible and flammable products, like paint, propane or LP, gasoline, should never be stored in the same room or close to this unit.

In order not to reduce energy waste, if water line is too long, insulate it and protect it from exposure to freezing condition. You can always wrap the heater with insulated jacket or blanket and reduce standby loss.

Install your tank type gas water heater only in the designated room, but not in bathroom, bedrooms or any unprotected outdoor location.

Venting requirements

Install your gas water heater close to the area of vent and where sufficient fresh air is provided for normal operation.

When planning to install a gas water heater keep in mind that if installing the unit in confined space, two openings has to be made for combustion and ventilation air. One opening is located within 12" above the floor and the other 12" from the ceiling. The total free area of the opening depends on heater's BTU.

Check also are the vent connectors properly secured, flue baffle and draft hood properly installed and on the right spot, connected to the chimney or vent pipe system, and on a safe distance from other combustible materials.

Note: Venting requirements, either power vented, direct vent or atmospheric are also dictated by code and usually HVAC installer has to install the venting system.

emergency plumber

Water and gas supply

Only when the gas and water supply are connected by a licensed plumber, the tank can be filled. When the air is removed from the heater and the system, the gas supply is activated and tested for leaks. Never use hot water heater unless it is completely full of water.

Check is the inlet gas pressure within the range that is specified on the rating plate.

Tip 1: You need a licensed electrician to connect the electrical portion of your gas water heater as you might violate your local code.

Tip 2: After you are done with gas water heater installation, always check the final connections for leak.

The gas regulator, control valve, has a 1/2" female threaded connection, which is usually typical for the most gas hot water heaters.

Per some codes, drip leg or sediment trap should be installed to collect any small particles or moisture that are present in the gas pipeline.

One of the important features installed on gas supply line, close to the water heater is gas cock or any other approved ball valve.

Connecting gas piping to the control valve of the heater can be accomplished by either flexible connector or black iron pipe.

How to inspect gas leak?

Use a solution of dish-washing soap and water and apply to the gas pipe connection. A leak will cause the soap to bubble.

TPR valve or temperature and relief valve are usually standard equipment for water heater manufacturers.

Final note: All gas water heater installation information you have found here are only for your reference. Our recommendation is to contact licensed installer or plumber, as the legal codes, regulation and manufacturer's instructions has to be followed.