Replacing a Water Heater

8 easy steps for tank electric water heater replacement

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Replacing a water heater that is using electricity for heating is very simple DIY home project. With our electric water heating tips and mini guide you don't need an expensive plumber for repair or replacement.

This guide will help you understand electric heaters better, so if it fails you will know how to substitute it with a new, better model that will work efficiently, last long and save you lots of money.

What we suggest here is not to start replacing a water heater immediately, but to double check all other options you have.

You might need to do some repairs instead; replace a part, fix a tank leak, or drain and flush, so buildup sediments are removed for efficient work.

Depends on the heater's manufacturer, usage, quality of water and other factors, tank's life expectancy can be shorter than expected. And it can surprise you.

Most of today's electric hot water heaters can last over 10 years but sooner or later the unit will either leak because of the rusty tank or malfunctioning tank's elements.

Replacing a water heater unit is not complicate at all, it requires a water line hook up and to connect some electric wires. The most difficult job is handling the heavy tank.

Replacing electric water heaters guide is made for people like you and we will lead you through 8 easy steps how to do the change. The same we did with 10 easy steps to replace a gas water tank heater. You can use this guide as a reference.


  • Pipe wrench

  • Tongue and groove pliers

  • Hacksaw or pipe cutter

  • Unions, fittings or flex connectors

  • Teflon tape or joint compound

  • Thin wire

  • Soldering torch

  • Wire brush

  • Appliance dolly

  • Garden hose

  • Level

  • Screwdriver

  • Voltage meter or 240-Volt Neon Test Light

8 Easy Steps How To

Replacing and installing a new electric hot water heater, is much simpler than trying to substitute the old gas unit; there is no work on a flue and gas line pipe involved.

Important: Take precautions when working with electricity, it is really dangerous, as the voltage of 240V is very high. For this home project you need basic plumbing skills and tools.

Step 1. Drain the Tank

Find the main water valve that supplies home and turn it off. Turn the electrical breaker (electricity to the unit) off. Open the hot and cold taps somewhere in the bathroom or kitchen above the unit (highest tap unit) and tap close to the unit (lowest point).

Take the garden hose and attached it to the heater's drain valve located at the bottom. Open the drain valve and let all the water from the tank out.

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Step 2. Disconnect the Electrical Wires

In the lower part of the electrical water heater there is an access panel and thermostat behind it. Once you remove the cover, check is there a current using a voltage meter or 240-volt neon test light, to be sure that the electricity is turned off.

At the top of the unit, remove the cover, and at the heater's junction box find two electrical wires, and disconnect them from the main electrical supply (usually connected with two wire nuts). Don't forget to mark them so you will know where exactly to connect them back when replacing a water heater.

Step 3. Disconnect the Plumbing Lines

Make sure to remember or mark where is the incoming cold water line and the outgoing hot water supply. If this electric unit is using rigid galvanized pipe, simply open unions close to the unit.

If using copper solid pipe cut the pipe just below the shutoff valve. Be sure to have the cut straight, take all the particles out and remove burrs and sharp edges. Prepare the copper pipe for soldering.

The easiest way is if the unit comes with the flexible copper pipe, as it is very easy to disconnect it with a wrench tool.

Step 4. Move the old unit out

Make some room for the new electric hot water heater, by moving the old unit out. The unit is heavy, especially if it had a problem with sediment buildup, so use wisely all the help needed and dolly cart.

If you need a help to choose the right electric water heater, there are some good information (a guide actually); how to choose the right tank unit, money saving tips, reviews of different brands and manufacturers here, or if using the navigation bar with links to Rheem, AO Smith and other manufacturers.

Step 5. Position a New Unit

If you were happy with the performance of the old unit, hot water production, recovery rate, efficiency; try to match features when buying a new one. If the characteristics are the same installation is easy. Bring the new unit in using a dolly cart. Line up the unit to the existing plumbing.

Step 6. Connect Electric Tank Heater with Water Line

First check, what type of water line you can install. If it is solid copper pipe, use it. Solder the pipe and copper fitting to the heater on one side and plumbing on the other. If you have to work with galvanized pipe, use a wrench and union to make connection. The easiest way is using the flexible copper pipe.

Step 7. Connect Water Heater with the Electrical Supply

Run the electrical cable through the clamp where the heater's junction box is and connect these two wires to the heater's wire connectors. Attach the ground wire to the ground screw.Tighten the screw on the clamp so it can hold the cable in the right spot.

Step 8. Before you start a water heater

Set the thermostat to the desired temperature, 120 F or 50 C is recommended hot water temperature, pres the reset button and put the access cover back.

Turn the water valve on and open the nearest hot faucet to remove any air pockets left, so it won't be trapped in the tank. When the water flows freely close the tap.

Replacing a water heater home project is now completed and your electrical unit is ready for the test shower.

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(All pictures are courtesy of