Though it’s not necessarily a plumbing emergency, life without a properly functioning hot water heater is just a little more uncomfortable. Learn the basics of this home improvement DIY project to get your home’s plumbing system back on track and enjoy those warm showers again.

how to replace water heater

1: Prep the tank

If your hot water heater uses a pilot light and is heated with gas, be sure to shut off the gas supply. It is safest to shut off supply to the entire house, so use the main shutoff valve. Turn off the water supply as well using the water main shutoff. Empty the tank by attaching a hose to the drain valve and empty your pipes by turning on the hot water tap on a faucet in your home.

2: Detach gas, water and exhaust

Using a pipe wrench, disconnect the gas and water supply lines that run to the water heater. Use a screwdriver or wrench to remove the exhaust vent pipe. Disconnect these pipes from the heater itself so you can reuse them with your replacement heater.

3: Remove the old heater

Though your water heater is now empty of water, it may still be heavy due sediment accumulation in the tank. Get help if you need it and dispose at a local recycling center or landfill.

4: Install the new heater

Carefully position the new heater so it is within connecting distance of your exhaust, gas and water pipes. Make sure the heater is at least 6″ away from any surrounding walls or furniture pieces. Test the heater to make sure it’s sitting perfectly level and adjust with hard nylon shims if needed.

5: Reconnect gas, water and exhaust

Wrap the heater’s heat trap threads with Teflon sealing tape and install color-coded fittings in the proper place using a pipe wrench. Connect the water supply lines to the fittings, taking care to match hot with hot and cold with cold. Reattach the exhaust vent pipe. Clean the gas inlet fitting so it’s clear of any debris and apply a thin, even layer of piping compound. Use one pipe wrench to hold the inlet in place and another to tighten the supply line. Apply more piping compound as you tighten.

6: Restore gas and water service to the heater

Turn on the water main. If water leaks, shut off the supply and tighten. Turn on the gas main. Check your gas connection for leaks by using bubble solution or a mixture of dish soap and water. Apply a layer around the gas pipe connection with a sponge. If bubbles form or noise escapes, gas is leaking. Immediately shut off the supply and tighten the connection. It is essential that you do not leave the new gas connection running without checking that it’s perfectly sealed, so perform this step separately from the water test.

7: Set the temperature control valve on the new heater


When you’re certain the gas pipes are secure with no leaks, fire up the heater’s pilot light. Use the temperature control valve to set your home’s hot water supply to a safe and comfortable level – to keep your heater in good condition, do not exceed 125 degrees.

If this plumbing DIY project seems a little too advanced for you, call a professional plumber. Your plumbing professional will have your old water heater taken out and the new one installed in no time.

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