“Eww… is that smell coming from the hot water?”
If you are picking up on a strange water heater smell, something like rotten eggs or a weird burning plastic scent, you are not alone. It is more common than you would think, and it’s definitely not something to ignore.
The truth is that smell is more than just annoying. It can be a sign that something is not right inside your water heater. It might be a chemical reaction taking place or a part that is beginning to fail.
The worst part is that it is not just a smell issue. It also affects the taste of your water, ruins your showers, and messes with your plumbing. It can even cause headaches for sensitive folks in your household.
So, let’s get to the root of the problem.
In this blog, we’ll dig into two important things:
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- What’s causing the smell?
- What can you do to fix it?
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Let’s kick things off with the first one: how the smell found its way into your heater in the first place.
Table of Contents
Most Common Causes Behind a Water Heater Smell
The primary offender for that unpleasant smell is sulfate-reducing bacteria that thrive inside your tank. Another reason is that when the magnesium anode rod starts to corrode, it reacts with the water and produces a strong, musty smell that lingers in your tap water.
Other factors could be adding to that bad odor in your water. Let’s have a detailed look at them one by one.
Cause #1: When sulphur-reducing bacteria grow
Here is a bit of simple science to explain what’s going on. Sulfur-reducing bacteria (SRB) feed on sulfur for energy and thrive in low-oxygen environments like deep wells, heaters, and plumbing systems.
As they consume sulfur compounds, they produce hydrogen sulfide gas, which is the stuff that smells like rotten eggs. They are most active when the heater is set too low or hasn’t been used in a while.
Cause #2: The Anode rod may be the problem
The magnesium anode rod, often called the rust protector, protects your tank by attracting corrosive elements. But there is a trade-off. The process can trigger chemical reactions that release the rotten egg smell. Water softeners can make it worse by eating the rod faster.
Cause #3: That burning smell could be electrical trouble
That sharp, hot water heater smell could mean something is overheating inside. Loose or worn-out electrical contacts can overheat, melt plastic parts, and leave behind a nasty burnt smell. That smell isn’t just bad; it’s a red flag for an electrical hazard and needs to be addressed immediately.
Cause #4 Sediment build-up also causes the stinky effect
As the water heats, minerals drop down and settle at the tank’s bottom. Unfortunately, so do bacteria. When this happens, it can give your hot water a weird, musty odor you just can’t ignore. It’s a common issue, especially if you haven’t flushed your tank in a while.
Cause #5: Contaminated water supply
Sometimes, it’s not your water heater to blame; it is the water itself. Contaminants like iron, sulfur, or chlorine in your supply can create strong odors when heated.
How to Fix Water Heater Odors: 5 Solutions For You
Below are the five most effective ways to deal with foul odors in your heater. These are simple, doable, and worth trying before calling in a pro.
Get Rid of that Sulfur Smell with a Quick Heat Reset
Small traces of hydrogen sulfide in your water are no big deal. But once it crosses 1.0 ppm (parts per million), things can get messy. According to the University of Georgia Extension (UGA), that much H₂S can mess with your plumbing and even change how your water tastes. So yeah, it’s worth fixing fast.
How to do it?
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- Switch off your heater to ensure safety, then drain all the water from the tank to clear out existing buildup and bacteria.
- Once emptied, fill the tank again with clean water and crank the heat up to at least 140°F. The higher temperature helps kill off odor-causing bacteria.
- Keep the water at that temperature for several hours (6 to 10 is ideal) to give the heat time to do its job.
- After the treatment period, turn off the heater and adjust the temperature back to your normal preference.
- Finally, drain the treated water, refill the tank one last time, and you’re good to go.
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If the smell still sticks around, it might be time to seek professional help and call a plumber.
Replace the Anode Rod
As discussed earlier, the reaction between a magnesium anode rod and your heater’s elements can encourage bacterial growth. Removing the rod entirely isn’t a smart move; you’ll just end up trading one issue (smell) for another (rust).
You could go for aluminum rods. They are easy on the wallet and last longer, though they break down quickly and leave more sediment behind.
For best results, you can try newer anode rod models designed to reduce odor and protect against corrosion. If your unit is older, upgrading to a newer rod type could help keep the stench in check.
Knock Out the Smell with a Chlorine Rinse
Chlorine probably isn’t the first thing you want in your water. But a one-time chlorination treatment can actually help get rid of that sulfur-like water heater smell for a while.
After adding a bit of chlorine bleach, just run your water until the smell clears. Make sure not to use your water for the next 24 hours because it needs time to do its thing. This trick works for now, but don’t count on it long-term. That smell might be back in a few months, so consider this a temporary fix, not a forever one.
Try a Water Softener if the Problem Runs Deeper
If that awful smell isn’t just coming from your unit but your tap water itself, installing a water softener or filtration unit could help.
These systems won’t strip every impurity out of your water, but they are great at cutting down on odor-causing bacteria.
You’ll also notice smoother skin and shinier hair, plus fewer spots on your dishes and clothes after washing. As a bonus, your pipes and fixtures might stick around longer since there is less mineral buildup wearing them down.
Wipe Down Dust Buildup
You can start by gently cleaning the exterior of your unit using a damp cloth or sponge. Stick to the outer casing and vents where dust often collects.
Let the unit run for a few days after cleaning. If the odor doesn’t clear up, get in touch with a professional plumber for a deeper inspection.
Get Electrical Components Checked
If you suspect something is off with the wiring or connections in your electric water heater, it is wise to call a licensed technician. They will replace any damaged wires, worn-out switches, or burnt-out parts to get things back to safe operation.
Once the connections are stable and the wiring is safe, the burning smell should completely disappear. You should see your system running clean and odor-free.
If All Else Fails – Replace the Heater
If you have tried every trick in the book and the odor just won’t leave, the last resort would be a full replacement. Your heater might be overdue for retirement.
Fortunately, with a reliable home warranty plan, this doesn’t have to be a costly headache. It will cover the cost of your heater replacement, making the process way easier (and more affordable) than you might expect.
Newer systems also run more efficiently and give you cleaner water. So if it’s time, don’t stress! Just check whether your warranty covers water heaters and move forward with filing a claim.
In a Nutshell: Time to Clear the Air
The mystery behind your water heater smell is likely simpler than it seems. From flushing the tank to checking components, you’ve got practical ways to fix it. Whatever the type of water heater, there is always a solution to tackle the odor issue.
But when the smell won’t quit, a replacement may be on the horizon. Not sure who to turn to? If you are backed by Select Home Warranty, you may already be covered for a full replacement. So, no stress, no sky-high costs – Sounds like a win? It’s time to get rid of that stench and breathe easier with cleaner, fresher water.
Disclaimer: The information in this article is intended to provide guidance on the proper maintenance and care of systems and appliances in the home. Not all the topics mentioned are covered by our home warranty plans. Please review your home warranty contract carefully to understand your coverage.
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