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Why Does My Hot Water Smell Like Rotten Eggs?
A sulfur smell that only shows up in the hot water almost always starts in the water heater. Here is why, and how it gets fixed.
Call Now – (949) 693-0298In this guide
- Bacteria react with the anode rod
- Water sat unused for days
- Temperature set too low
- Fix: flush and disinfect the tank
Why does my hot water smell like rotten eggs?
A rotten egg smell in hot water is usually hydrogen sulfide gas. It forms when harmless sulfate-reducing bacteria in the tank react with the magnesium anode rod. The smell is worse after the water sits unused or when the temperature is set low. Flushing the tank and changing the anode usually fixes it. Call (949) 693-0298 for help.
Our water heater repair Mission Viejo techs carry replacement anodes for most brands, so this is usually a one-visit fix.
Is it the water heater or the water supply?
Run cold water from a few taps. If the cold water smells fine and only the hot water smells, the cause is in the water heater. If both hot and cold smell, the problem is in the water supply or a drain, and you should call your water provider.
- Hot water only: the water heater, usually the anode rod.
- One sink only: often the drain, not the water. Smell the water in a glass away from the sink.
- Hot and cold: the supply. Contact your water district.
How does the anode rod cause the smell?
The anode rod is a metal rod inside the tank that corrodes on purpose so the steel tank does not. Most tanks ship with magnesium rods. Bacteria in the water can use the electrons from that magnesium to turn sulfate into hydrogen sulfide, which gives off the sulfur smell.
The fix is often to swap the magnesium rod for an aluminum-zinc rod, which slows the reaction. Do not remove the anode completely. Without it, the tank rusts out fast and the warranty is usually voided. An anode rod replacement costs about $200 to $450.
Can you fix the smell yourself?
You can try a few safe steps. Raise the temperature to about 120 degrees if it was set lower, run the hot water at each tap for a few minutes, and flush the tank to clear sediment where bacteria live. If the smell comes back within a few days, the anode and a tank disinfection are the next steps.
Avoid pouring chemicals into the tank unless the manufacturer's instructions allow it. Hot water is scalding, so take care when draining. Our water heater flush guide walks through the basics, and a professional flush costs about $120 to $250.
When is the smell a gas leak instead?
Natural gas has a rotten egg odor added so you can smell leaks. If you smell it in the air near the water heater, not just in the hot water, treat it as a gas leak. Do not light anything or flip switches. Leave the home and call the gas company from outside.
The SoCalGas safety page explains what to do if you smell gas. Once the gas company says it is safe, we can check the gas valve and connections. A gas valve replacement costs about $350 to $650.
When should you replace the water heater?
If the smell comes with rusty water, leaks or a tank over 10 years old, a new heater may be the better choice. A standard 40 to 50 gallon tank costs about $1,900 to $3,800 installed. A newer tank with a fresh anode rarely has the smell.
Learn more on our water heater replacement mission viejo page. If you live in the newer villages, see water heater repair in Rancho Mission Viejo.
Frequently asked questions
Is it safe to shower in water that smells like rotten eggs?
Low levels of hydrogen sulfide from a water heater are usually more of a nuisance than a health risk, but have it fixed. If you smell gas in the air, leave and call the gas company.
Will a new anode rod stop the smell?
Often, yes. An aluminum-zinc anode slows the reaction that causes the smell, especially after the tank is flushed.
Why does my hot water smell after vacation?
Water that sits warm in the tank for days gives bacteria time to grow. Run the hot water at each tap for a few minutes when you get back.
How much does it cost to fix a rotten egg smell in a water heater?
An anode rod replacement costs about $200 to $450, and a flush about $120 to $250, in Mission Viejo.
Talk to a water heater pro now
Questions about your water heater? Call a local pro in Mission Viejo, CA. Open 24 hours a day, 7 days a week.
(949) 693-0298 Call Now – (949) 693-0298