How to Replace an Electric Water Heater
Learning how to replace an electric water heater involves disconnecting the electrical and plumbing connections, removing the old unit, and installing a new one, all while adhering to proper safety measures.
For a professional, a straightforward water heater swap typically takes about 90 minutes. Switching between a tank and a tankless system can extend that to 4 to 8 hours. Electric water heaters don't need gas venting, which simplifies the process compared to gas units. Professional installation handles code compliance and protects your warranty.
When to Replace Electric Water Heaters
Most electric water heaters last 8 to 12 years with regular maintenance. Age alone isn't always the deciding factor—a 10-year-old unit running perfectly might have years left, while a 6-year-old unit with rust in the hot water needs immediate replacement. Water quality, usage patterns, and maintenance habits all affect lifespan more than the number on the warranty sticker.
Installing an electric water heater without having a permit can void your homeowner's insurance coverage if something goes wrong.
Types of Electric Water Heaters (Tank vs. Tankless)
Many homes have tank water heaters, but tankless models are becoming more common for replacements. Here's how they differ:
- Tank Water Heaters: Store 30 to 80 gallons of hot water so it's ready when you turn on the tap—they work with standard home electrical and cost less upfront than tankless.
- Tankless Water Heaters: Heat water the moment you need it instead of keeping a tank full, which saves space and lowers your electric bill, but might require an electrical panel upgrade.
Signs Your Water Heater Needs Replacement
Rusty or discolored hot water can be a sign of bacteria in your water. If you notice this, contact a certified contractor to assess the situation. Popping, crackling, or unusual noises can mean sediment has built up at the bottom of the tank. The heating elements have to heat your water through layers of mineral deposits.
Flushing might buy you some time, but loud noises that don't go away mean replacement is coming soon. Leaks around the base of your tank are another clear sign. Small drips can turn into floods fast once the tank starts failing. If you see water pooling around your water heater, start shopping for a replacement.
Tools, Materials, and Safety Preparations
Replacing an electric water heater requires pipe wrenches, voltage testers, and specific plumbing materials. Professional installers handle the work for good reason—240-volt electrical connections and local building codes make this more complicated than swapping out a faucet.
Tools for Water Heater Replacement
Pipe wrenches in 12-inch and 18-inch sizes handle water line connections, while adjustable wrenches work for smaller fittings. Wire strippers, voltage testers, and screwdrivers manage the electrical side. A non-contact voltage tester confirms the power is off before touching any wires.
Key Materials and Parts List
New water heater installations need a few key materials:
- Flexible Water Supply Lines: Braided stainless steel lines connect more easily than rigid copper pipe and handle the hot water without issues.
- Thread Tape: Seals threaded fittings to prevent leaks at connection points.
- Temperature and Pressure Relief Valve: Comes with your new water heater and must be installed fresh—don't reuse the old one.
- Electrical Conduit and Wire: Some jobs need updated wiring to meet current building codes.
Safety Precautions and Code Requirements
The power needs to be turned off at your circuit breaker and tested with a voltage tester before touching any wires—240 volts can be deadly. Don't work around water or wet floors. Most areas require permits for replacing water heaters.
Building codes cover things like clearance space, electrical specs, and required safety devices. Call your local building department to find out what's required in your area—skipping permits can cause problems when you sell your house or file an insurance claim.
Replacing Your Electric Water Heater
Removing the old water heater takes about an hour after draining the tank and disconnecting everything. Installing the new unit goes faster since the plumbing and electrical are already in place.
Removing the Old Electric Water Heater
The old tank gets drained through a hose connected to the bottom drain valve. A hot water faucet opened somewhere in the house lets air in, so the draining goes faster.
The electrical connections come off after verifying that the power is shut off. Professional installers photograph the wiring before disconnecting anything and label each wire to avoid confusion during the new installation.
Installing the New Water Heater Unit
The new water heater goes in the same spot as the old one, with enough clearance around it for future maintenance. It needs to sit level so connections don't get stressed. Shims handle uneven floors.
The temperature and pressure relief valve gets installed with pipe thread compound on a new water heater. The discharge tube from that valve runs down to within six inches of the floor, or a drain, so any pressure release doesn't spray hot water everywhere.
Electrical Connections and Plumbing Hookup
The electrical connections get hooked up after double-checking that the breaker's still off. Before any electrical connections are made, the tank must be completely full of water, all air purged, and inspected for leaks. Connections are made at the junction box. Electric water heaters run on 240 volts with a dedicated circuit. The two hot wires and ground wire connect at the junction box terminals.
All connections must be tight, with no exposed wire. The water supply lines connect to the hot and cold ports on top of the tank. Professional installers check every connection for leaks before turning the power back on.
Water Heater Selector Quiz
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Testing, Maintenance, and Troubleshooting
After installation, the water heater needs testing before you can use it. Turning on the power too early with an empty tank burns out the heating elements.
Initial Testing and System Startup
The circuit breaker gets turned back on once the tank's full of water. Electric water heaters run on 240 volts, so proper voltage at the heating elements matters. The upper element heats first, then the lower one kicks in. Water temperature should climb gradually over the first few hours without any strange popping or banging sounds.
Regular Maintenance Tips for Longevity
Water heaters need annual flushing to clear out sediment buildup at the bottom of the tank. The temperature and pressure relief valve is tested twice a year to make sure it opens and closes properly. A stuck or leaking relief valve can't release dangerous pressure and needs replacement.
Common Issues and When to Call a Professional
Some problems need a licensed plumber or electrician, not a DIY fix:
- Electrical Problems: Tripped breakers that won't reset, burning smells, or sparking connections need a licensed electrician right away.
- Water Leaks: Leaks that appear after installation mean connections weren't tightened properly and need fixing before they cause damage.
- Warranty Protection: Warranties can require professional installation to stay valid, and a licensed installer handles permits and local code requirements.
Find an A. O. Smith Certified Installer
A. O. Smith has been making water heaters for over 80 years at the world's largest water heater factory in Tennessee. Our certified installers handle replacements professionally so your warranty stays valid and everything meets local building codes. Connect with a local installer to schedule your water heater replacement.
Rebates & Tax Credits
Rebate and incentive programs provide savings to consumers for the purchase of water heaters that meet certain energy efficiency standards.
Use A. O. Smith's Qualified Manufacturer (QM) code A5X5 for federal tax return form 5695.
Need Help From A Pro?
A. O. Smith water heaters are professionally installed by local independent contractors.
Frequently Asked Questions
Electric water heaters last 8-12 years, depending on water quality and how much hot water your household uses. Annual flushing and pressure relief valve testing help extend the tank's life.
Professional installers handle the electrical hookup, plumbing connections, permit filing, and local code compliance. They protect your warranty, haul away your old unit, and test everything before leaving.
The installer drains and removes your old hot water heater, positions and levels the new water heater, makes the electrical and plumbing connections, installs the pressure relief valve, and tests for leaks before turning the power back on. The complete job typically takes 4 to 6 hours.
Annual tank flushing clears out sediment buildup at the bottom. The pressure relief valve gets tested once a year to confirm it opens and closes properly. Regular maintenance extends tank life and keeps efficiency up.