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How to Tell if Anode Rod Is Bad

If you know about anode rods, then you know that they need to be replaced. After all, a lot rides on replacing this one part if you value the longevity of your water heater! On average, they need to be changed every 3-5 years. But with a two-year range the fact that some water qualities make the rods degrade faster and it can be hard to know when exactly to change this all-too-important part

There are plenty of ways to tell that your anode rod needs replacing. The most straightforward check is simply to do a visual inspection. However, there are other signs you may have noticed that you might not have known could be indicators of a rod gone bad.


Orange/brown water, air in the pipes, suddenly smelly water, or a banging sound from the water heater indicate a bad anode rod. Keeping a record can help indicate when the anode rod will be going bad. Visual inspections are very reliable. In severe cases, a leaking tank will show the anode is bad.

Keep a Record of Changes

Keeping a record of when you replace your anode rod can help you to estimate when the rod will next need replacement without needing to check it all the time.

You can also “get to know” your water heater. If your water source and water heater do not change, then you can usually quite accurately predict when next the anode rod requires replacement.

For example, if you know that the past two times, you needed to change the anode rod after approximately 4 or 4.5 years, then the chances are that you will only need to change it again in 4 or 4.5 years.

How Often Must Anode Rods Be Changed?

The average anode rod will only need replacement every 3-5 years. However, there are many variables that can increase or decrease the lifespan of a rod.

One of those variables is water hardness. Naturally, hard and soft water are relatively equal when it comes to the rate of corrosion, assuming you use the correct type of anode rod.

However, if you use a water softener, your anode rod will need very frequent replacement.

This is because water softeners replace the minerals in hard water with sodium. While this does, of course, soften the water and reduce the buildup of limescale, the sodium will greatly increase the rate of corrosion as a tradeoff.

This may lead to an anode rod needing replacement every 1-2 years, though this could actually be even more frequent if your water is being over-softened.

Because water softening causes such a big increase in the speed of corrosion, it is recommended to up inspections, even checking it as often as every 6 months.

Visual Inspection

It should be relatively easy to tell when an anode rod has gone bad just through visual observation. 

Once an anode begins to corrode, it will begin to change color and texture. Rather than a shiny silver, its surface will begin to take on a coppery brown color.

Additionally, the rod’s smooth surface will begin to develop a rough and porous texture, almost like a cross between sandpaper and a sponge. 

water heater flange with anode

Lastly, the rod will begin to thin as its material begins to corrode away.

If your rod has noticeably thinned on top of developing a rusty appearance, it may need changing. Measure your rod; if it is only ½” in diameter or less, it should be changed.

If you are able to see its thin steel core at any point along its length, or if it is coated in a white calcium substance, it has definitely gone “bad” and needs replacement before it breaks off or your tank begins corroding instead.

How to Check Your Anode Rod

Anode rod removal is somewhat universal, though there may be slight differences between models, or if you have complications like a seized anode

Generally, however, you will follow these steps:

  1. Disconnect the power (electric heater) or gas (gas heater) to your water heater.
  2. Close the main water supply or the cold water inlet.
  3. Connect a hose to and drain the water out of your heater. (Use caution, this water will be very hot!).
  4. Locate and loosen the hex head bolt on top of your heater. Various tools like a pipe wrench, a breaker bar, or an impact driver may be needed.
  5. Pull out the anode to inspect. Reinstall the rod if it appears fine, or replace it with a new rod if it appears worn.

Water Smells Like Rotten Egg

If you’ve been noticing that your water smells like rotten eggs, it’s possible that the problem is related to your anode.

This stinky smell might remind you of sulfur—because it is! To be more specific, the smell is caused by hydrogen sulfide gas. There are two main ways this gas can become a problem in your water.

Some water supplies, particularly untreated water supplies like well water, contain high amounts of an ion called sulfate. This sulfate is turned into hydrogen sulfide gas once broken down by sulfur-reducing bacteria.

Alternatively, your anode rod has corroded. Due to corrosion, the metals (aluminum and magnesium) used for anodes can react with the sulfates in the water to create hydrogen sulfide gas.

Essentially, it can’t hurt to check on your rod’s condition if you’re smelling sulfur. Either your rod is corroded and needs replacement, or you should look into getting a different type of rod altogether. 

Are You Using the Correct Anode Rod?

While smelly water can sometimes be corrected with anode replacement, there are other ways to prevent its occurrence. 

First and foremost, ensure you are using the right type of rod for your water. While magnesium rods are excellently suited to softened water and aluminum rods are perfect for harder water, neither are the correct rod for smelly water.

In these cases, you should consider choosing to install a zinc alloy sacrificial anode rod or a powered anode rod instead.

Both zinc anodes and powered anodes destroy sulfur-reducing bacteria.

If you are already using a zinc alloy anode and the smell returns, it is a good indication that the metal has been depleted and it’s time for a new rod.

Hot Faucets Splutter (Air in the Pipes)

If your cold water is running without a problem, but your hot water splutters and pours out of the faucet inconsistently, then you’ve got air in your hot water line.

This air is hydrogen gas, which is created through the reaction of certain material in the water with the metal of the anode rod.

This is more likely to occur in well water, which is often untreated, and if the anode rod is magnesium. This is because magnesium is the most reactive material used for sacrificial anodes. However, it may still occur with aluminum rods.

There are many potential fixes to this issue. Like with smelly water, one of those potential solutions could be the close monitoring of and replacement of anodes before they are severely worn out and able to contribute to excessive hydrogen gas production.

Alternatively, swapping to a powered anode can once again be a more permanent solution. This is because a powered rod is made of titanium, a metal with extremely low reactivity. 

As powered anodes are non-sacrificial and designed for long-term use, they will prevent hydrogen gas buildup from corrosion as well.

Brown Tint to Hot Water

If you’re noticing that only your hot water has an orangey or brown discoloration, then your anode rod is likely to be past its due date.

water heater orange water leaking

This brown tint is usually caused by rust or sediments within the water tank. Anode rods generally prevent the majority of this buildup by attracting corrosive elements to themselves.

If your rod has worn out, your tank becomes the next “victim.” Any loose rust buildup and debris will find its way into your water lines, creating the brown color.

If you are noticing that it is not just your hot water that is discolored, or if your discoloration is a color other than a rusty brown, then you have a different problem. It is likely your water supply itself that is the issue, not just your anode or your water heater.

Banging Sound From Inside Tank

Banging noises from within the tank are yet another indication that your rod has failed and needs replacement. 

There are of course several potential causes of banging or popping noises, some of them harmless. However, If it distinctly sounds like something is knocking against the inside of your water heater or rattling within it, then that’s probably exactly what’s happening. 

That noise is likely your anode rod itself, or perhaps multiple pieces of it, that have broken off and are floating freely within the tank. 

This happens when your anode has corroded too much without replacement, creating thin weak points at which it is prone to separation.

It is up to you to decide how to handle these broken pieces; whether they are fished out, broken up until they are small enough to be flushed, or even simply left in the tank.

Any of these options are viable, but note that if you leave your broken anode inside the tank, you may continue to hear it make noise until it has fully deteriorated.

Water Heater Has a Tank Leak

Of all the indicators of a depleted anode rod, a leaking water heater tank may be the least desirable.

It’s important to first check on your rod if your tank is leaking. If it is completely depleted, then it becomes more likely that your tank has rusted through from the inside and you need to get a new water heater altogether.

water heater tank leaking. tools on the ground

Don’t fret too early, though! It is possible for a leaking tank to be caused by other, less severe issues, though a fix will still be necessary, and perhaps even a replacement.

For example, your tank could be leaking at the drain valve, or the inlet and outlet connections. In this case, it’s likely just loosening over time that has created a leak and can be quickly fixed.

Other leaks could be caused by the internal lining (if your tank has one) cracking, or old age and gradual wear finally catching up to the heater despite the presence of an anode. Leaks caused by reasons like this will still require full water heater replacement, even if not caused by the anode.

Sources

https://www.applewoodfixit.com/blog/anode-rod-water-heaters-secret-weapon/

https://anyhourservices.com/blog?post=water-heater-maintenance-anode-rod

https://www.artdouglasplumbing.com/what-should-you-do-if-you-have-brown-water

https://bosworthco.com/dealing-with-brown-water/

https://www.corroprotec.com/blog/air-in-hot-water-line/

https://www.corroprotec.com/blog/sulfur-smell-in-hot-water/

https://extension.uga.edu/publications/detail.html?number=C858-15&title=Removal%20of%20Hydrogen%20Sulfide%20and%20Sulfate

https://www.masterwater.com/hydrogen-sulfide/

https://www.plumbingplus.net/blog/2017/september/maintaining-your-tank-type-water-heater/

https://www.plumbingsupply.com/understanding-water-heater-anode-rods.html

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