Replacing a Water Heater

Plumber Pipe and Adjustable Wrenches on Water Heater Gas Line
What You'll Need
Water heater
Vent pipe fittings
Gate valve
plumber's tape
pipe cutter
Soldering torch
T&P relief valve
Water pipe fittings
Water and gas flex connectors
Pipe wrenches
Adjustable open-end wrench
Sweat-soldering supplies
Appliance cart, dolly or hand truck
Garden hose (optional)

Water heaters, especially older ones, may seem to stop producing enough hot water for your home. Newer water heaters are not only more cost-effective by saving energy, but come with larger tanks to meet the needs of your home and have been upgraded with quite a few safety features. Replace you old water heater and notice the difference right away.

Step 1 - Turn off and Drain the Old Water Heater

Turn off the power to the water heater, depending on whether it’s gas or electric. This will prevent injuries when removing the old unit. Turn off the gas valve that goes to the water heater if its gas, or turn off the power switch in the breaker box if it’s electric. Also turn off the water that runs to the water heater, so that the tank doesn’t try to refill itself when you empty it.

Step 2 - Drain the Water

Drain all of the water from the hot water heater using a faucet inside the house. Turn on the hot water and run it all out until the water becomes cold or lukewarm. You can also empty the tank by attaching a hose to the hose bib on the outside of the water heater and running it outside. Make sure the entire tank is empty before you try to move the old water heater.

Step 3 - Make Sure the Pilot Light Is Out

The pilot light, located in the base of the water heater, is what heats up the water. It’s basically a small fire in the bottom that can be very hazardous if it isn’t out before moving that water heater. This is very important because power or gas running to the water heater can keep the pilot light lit—which can cause a serious fire or life-threatening injuries.

Step 4 - Disconnect the Old Water Heater

Since you’ve turned off the gas or electric power that runs to the water heater, the next step will be to disconnect the old water heater from the gas pipe or electric that come from the wall. Loosen and unscrew the “union” in the gas pipe, where the wall pipe and water heater pipe connect, if you have a gas water heater. If your water heater is electric, you will have to remove the small electric panel from the water heater with a screwdriver. Once the panel is off, you should be able to see where the wires from the wall have been spliced with the water heater wires. Go ahead and disconnect them by removing the caps and disconnecting the wires. If the wires aren’t labeled, it’s important to do that now with different colored tape or a dab of paint. Again, make sure the power to the water heater is turned off at the breaker box for safety before you do this.

Step 5 - Cut the Water Pipes

You’ve already turned off the cold water valve that runs to the water heater, so no water should be flowing in or out of the hot and cold water pipes. Use a razor blade to cut the pipe insulation away from the pipes if they are covered in foam insulation. Then, you’ll have to use a pipe cutter to cut through each pipe, about 5-10 inches away above the water heater if there are no unions on the water pipes. This will allow you to pull the old water heater out.

Step 6 - Bring in the New Water Heater and Remove the Old

Bring the new water heater in on a dolly, leaving space for you to take out the old one. Make sure the old water heater is completely disconnected before attempting to move it. Once you’ve moved the old water heater out of the way on the dolly, put the new one in its place.

Step 7 - Line up Everything

With a gas water heater, line up the gas line on the new water heater with the gas line pipe coming from the wall. For an electric water heater, make sure the electrical wires from the wall will reach the wires in the new water heater’s electrical panel. The water hose bib should also be accessible for future use, if possible.

Step 8 - Connect the New Water Heater

Connect the new water heater using new piping connectors (you can get fitted, snake-like ones that easily connect and screw on). Use one for the hot water line, and one for the cold. With a gas water heater, use the right size pipe to connect the gas line. If electrical, reattach the power wires the same way you dismantled them.

Step 9 - Tighten all Connections and Turn Everything On

Use a wrench to tighten any and all connections between pipes you’ve reconnected. Once secure, turn the water back on to fill up the hot water tank. Once the water heater is almost full, go ahead and turn on your gas or electrical to turn on the water heater. You should have hot water from your new water heater within an hour.

Step 10 - Set up the Pressure Release

You may have to do some soldering here in order to attach a new pipe to a fitting properly. The end of this pipe should be at least six inches from the floor. If you need assistance with this, you may want to get the help of a professional. This discharge tube or pipe helps release any excess heat and water from the water heater and is essential. With a gas water heater, ensure the flue pipe is reconnected properly, open, and pushing air outside the house.