Replacing your own water heater: City codes and required steps

In this How to Article, True Plumbing describes the process and politics involved with replacing your own water heater in the state of Texas.

There are laws that you need to take into consideration in Texas regarding water heater replacement. Simply put, no water heater can be changed without a city inspection. It is easiest if a licensed master plumber replaces a water heater anywhere within city limits, BUT as a homeowner you have the right to do upgrades and repairs on your own home and can replace your own water heater - assuming you ensure your installation with meet city codes.

How do I get the appropriate permit?

You must first go to your city hall and pull a homeowners permit to replace your water heater. You should also request any information they have regarding applicable city codes.

As professional plumber, we know exactly how your particular city wants it done. Codes change yearly as new, safer ways of doing things become apparent and as citys deem new requirements are appropriate. Because of this, plumbers must take a 6 hour class every year before renewing their license just in order to keep up with all recent changes.

Now, I do not speak for city inspectors or city policy and all plumbing codes are subject to local interpretation and the city is the final authority.

Replacing the water heater

If you thought your water heater could just be plugged in and your old heater discarded, you need to read the following information. We do not cover the basic installation, but we do cover the preparations required in order to keep your water heater up to code.

Combustable Air Source

When I go to change a water heater, the first thing I do is check the combustion air source (for gas water heaters). You must have 110 square inches of combustion air dran from the attic to the top of the water heater. It must also have 110 square inches drawn from the attic to the botom of the water heater. This can be achieved by using (2) 6" duct pipes. One from the attic to the top of the heater, and one from the attic to the bottom of the water heater with 1 foot of clearance from the pipe to the bottom of the water heater.

All other air must then be sealed off from entering the water heater compartment. Common problems are louvered doors or lower combustion pulled from the house.

The Drain Line

You then need to work on the drain line. A pan goes under the water heater which is attached to a 1" drain line which is run out of the home, or if permissable in your city, can terminate in your garage.

If it is impossible to get this line out, you can use a flood stop device if it is preapproved by your city. Some cities also require the flood stop to shut off gas if water is detected while others allow only the water to be shut off. Both of these valves are very expensive, with the gas valve being the most expensive. These should only be used if there is absolutely no way to get your drain pan line out correctly.

Your drain line must be installed with a minimum of 1/4" per foot of fall all the way to the termination destination.

The Pressure Release Valve

Now turn your attention to your temp pressure release valve line. This line connects to the temp pressure release valve which is your emergency pop off valve. This valve is activated if the thermostat malfunctions and the water is allowed to be heated out of control.

If this were to happen unchecked, the water would boil and turn your water heater into a bomb.

The importance of this line cannot be understated. Code requires this line be made of a material that can withstand boiling hot water and pressures above 80 psi. The following materials may be used in this application:

  • 3/4" hard drawn type M or better copper
  • 3/4" CPVC

Both must fall 1/4" per foot to the termination point outside of your home and must not be in an area that is heavily trafficked and must terminate no lower than 6" and no higher than 18" from the ground.

Cut off valve

I then look at replacing the cut off valve and isntalling the new heat sinks which are nothing more than 4" loops in the pipe. Coming from the cut off valve, the pipe runs up 4" then over and then down into the water heater. This creates a trap where the heat from the hot water rises up and dissipates through the outside of the pipe and prevents the hot water from heating the cold water outside of the system.


Only after considering all of these facts, the new water heater can then be considered installed. As you can see from this article, changing your water heater is more than just disconnection a couple of lines and plugging the new own in!

I highly suggest that you call a qualified professional to replace your water heater. If you were to not install your water heater properly, according to local code, the city will require it to be redone until it meets code. In the long run, it is cheaper to just call a professional!