How to Inspect and Replace a Sacrificial Anode Rod (Every 3-5 Years)



The water heater anode rod is a key part of keeping your hot water tank in good shape and extending its service life. Without regular replacement, however, you may risk excessive corrosion, leaks and damage to your plumbing system. Learn how anode rods work, when they need replacement, and when to call Service Champions for help.

What Is a Sacrificial Anode Rod?

The sacrificial anode rod is an essential part of your water heater. Typically made of magnesium, zinc, or aluminum, the anode rod extends through the heater and protects it from sediment damage.

Using an electrochemical process, the anode rod attracts corrosive elements. Since water attacks the steel-lined water tank and any metal pipes in your home, a more reactive (less noble) metal than the tank is best for the sacrificial anode rod. As water-borne elements corrode the metal anode rod, your tank should see minimal wear from water and minerals, fewer repairs, and improved longevity.

When to Replace Your Anode Rod

Replacing your anode rod regularly is important for ensuring proper function and lifespan from your water heater. Consider these key factors when determining whether to replace the water heater anode rod.

Timeframe

Anode rods require routine inspection and replacement, approximately every three to five years. Without proper maintenance, the anode rod loses its ability to divert damaging particulates from your tank and can accelerate rust and corrosion from chemical reactions, excessive heat, and imbalanced pH levels.

The exact interval depends on various factors that can accelerate the corrosion process, such as:

  • Water quality (hardness)

  • Anode rod material

  • Water usage

  • Water softener use

  • Naturally occurring sediment and minerals

  • Water pH level

Visual inspection

Check your water heater and water anode rod for corrosion and rust at least once per year. If the rod appears heavily worn and degraded to its core wire, it’s ready for replacement. Look for other signs, such as calcium build-up — light build-up is normal and easily cleaned away, but heavy build-up suggests it’s no longer effectively managing the water’s mineral content.

Tank age and condition

Water heaters can last between 10 and 20 years before they require replacement. If your water heater is approaching its estimated lifespan, consider replacing the anode rod earlier than usual to limit tank corrosion and extend its operational life.

Performance problems

Poor water heater performance can sometimes stem from an anode rod that’s overdue for replacement. If you notice signs of poor performance, such as discolored or rusty water, sulfuric or rotten egg smells, popping sounds from the tank, or high heating bills, inspect your water rod to determine if it needs replacement.

Manufacturer recommendations

Check the manufacturer instructions for maintenance guidelines for your water heater and anode rod. In some cases, manufacturer’s require replacement at specific intervals to maintain water heater warranty validity. Missing out on due maintenance can leave you without warranty coverage and on the hook for repairs.

How to Replace a Sacrificial Anode Rod

Using basic tools and straightforward steps, you can learn how to replace the anode rod to protect your water heater.

1. Gather tools and materials

Collect the tools and materials required to perform the replacement. These include:

  • Replacement sacrificial anode rod

  • Pipe wrench

  • Adjustable wrench or socket wrench set

  • Bucket or hose

  • Plumber’s teflon tape

2. Turn off water and fuel supply

Locate the gas line near the bottom of your water heater. Turn off the gas by rotating the valve clockwise — it should be perpendicular to the pipe and set to the pilot position. If you have an electric water heater, locate its corresponding breaker in the main service panel and flip it off.

After shutting off the gas and electricity, locate the cold water supply, normally on the upper right side of the unit, and turn it off. The cold water line may have either a ball valve, a handle that goes parallel or perpendicular to the pipe, or gate valve, a handle that you have to spin. Either way, turn the valve clockwise until it comes to a stop.

3. Drain water

Drain a few gallons of water using a bucket or hose. Attach the garden hose to the boiler drain on the bottom half of the tank and run the hose outside or to a drain. Open a nearby hot water faucet to ease pressure on the tank and allow water to drain from the heater.

Some boiler drains have a handle to open the valve, and others require you to use a flathead screwdriver. If your tank has excessive sediment, consider draining the tank and flushing it out.

4. Locate anode rod

The anode rod is usually located on top of the water heater — look for a hexagonal plastic cap that marks its location. You may need to remove the entire lid to find it. 

Some water heaters have the anode rod on the side and accessible via a separate port. If you’re unable to locate it, refer to the unit’s user manual or contact a plumber.

5. Loosen the hex head and remove the anode rod

Loosening the hex head can take some muscle — most anode rods remain in place for several years. The hex plug head on top usually requires a 1-1/16” (27mm) socket. If it’s difficult to remove, use a pipe wrench or breaker bar for extra leverage and have another person weigh down the tank.

Don’t bang on the water heater or use penetrating oil; these tactics can damage your heater or contaminate your water supply. In some cases, the anode rod is too difficult to remove without causing damage and requires professional plumber assistance.

With the hex head loosened, you can pull out the anode rod. If your ceiling is low or you have limited room, you may have to bend the anode rod to remove it. If the anode rod won’t come out because of attached sediment, it’s likely still functional and doesn’t need replacement.

6. Install new sacrificial anode rod

Use several layers of plumber’s tape to securely wrap the joint threads of the new anode rod. Most heaters don’t have enough clearance for a rigid anode rod and require a flexible rod. Slide the anode rod into place in the top or side of the water heater and thread it by hand for several turns. Then, use the socket wrench to tighten about half a turn. Don’t tighten so much that the water heater begins to move or twist.

7. Turn on water and fuel supply

Close the drain valve, and remove the garden hose from your water heater. Open the cold water supply valve to refill the tank, keeping the hot water faucet from earlier open. As the tank refills, the faucet should make sputtering sounds as it pushes air out until it runs smoothly again, at which case you can close it.

Look for leaks around the anode rod and connections, tightening it or layering more tape as needed. Restore power to your water heater — turn on the breaker for an electric unit, or relight the pilot light for a gas unit.

DIY vs. Professional

Replacing the sacrificial anode rod can be a simple task with basic tools and plumbing understanding. If you’re unsure about the replacement process, however, consider hiring a certified plumber to help. They can efficiently replace the anode rod and rule out other plumbing concerns if you’ve noticed performance problems.

Choosing the Right Anode Rod for Your Water Heater

Selecting the appropriate anode rod for your water heater involves several key factors, including:

  • Material: While magnesium rods are standard for normal water conditions, other rod materials can offer better corrosion resistance, improved durability, and protection from sulfates and odors.

  • Water quality: Hard water may benefit from an aluminum or combination rod. Soft water can corrode magnesium rods quickly and may benefit from zinc or aluminum-zinc rods.

  • Manufacturer recommendations: Check your water heater’s specifications for the correct type and size for your anode rod replacement.

Maintain Your Water Heater With Help From Service Champions

Regular anode rod replacement and water heater maintenance is key for keeping your hot water running properly. Serving Northern California, Service Champions provides customers with competitive financing and high-quality plumbing services. Contact us today to get started.

Frequently Asked Questions

Can I wait longer than five years to replace the anode rod?

Waiting too long to replace the anode rod isn’t recommended as it can place extra wear on your water heater and result in damage or bursting.

Can I replace the anode rod myself?

You can replace the anode rod yourself by following safety precautions and manufacturer requirements. If unsure, hire a plumber for fast and stress-free replacement and peace of mind.



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