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How to Remove Sulfur Smell From Hot Water Heater? – 5 Methods

Fact checked by Stephen Conklin

how to remove sulfur smell from hot water heater

Hot water that smells like rotten eggs can make shower times and dishwashing chores less appealing (even almost repulsive). Naturally, homeowners would want to know how to remove sulfur smell from hot water heater systems.

Water that smells bad reflects sulfur-producing bacteria, making the water unsafe for human consumption. The good news is we have five proven ways to address the smelly issue and restore the glory days of warm, pleasant showers.

Please read on.

Table of Contents

Step-by-Step to Remove Sulfur Smell From Hot Water Heater


What to prepare

Professional and DIY solutions exist to help eliminate the unwanted sulfur odor from water heaters and similar systems. Each method has unique resources, so we’ll highlight them as we present the five techniques for eliminating the rotten egg odor from hot water heater units.

What to do:

Don’t worry if your water heater smells like sewage now. The following methods should help you reclaim your water-heating appliance’s optimum functionality – delivering hot, pleasant-smelling water.

Method 1. Crank up the thermostat to the highest possible setting (above 140 degrees).


This trick is a temporary solution to a water heater that smells weird. It creates an environment less forgiving to sulfate-reducing bacteria (SRB) in the hot water tank. The high water temperature inhibits bacterial growth, making them less likely to release sulfur.

Unfortunately, this solution could lead to bacterial regrowth once you dial down the thermostat. Compared to other home remedies, cranking the temperature to the highest setting could also lead to burn injuries.

Still, dialing the thermostat is a noteworthy solution to address a water heater that smells like wet dog.

  • Check the water heater’s manual for the proper way of adjusting the appliance’s thermostat.
  • Use the water heater’s thermostat controls to adjust the temperature setting to the highest level.

Caution: Please warn household members not to use the water heater until you readjust the thermostat settings. Doing so can cause thermal injuries.

Method 2. Treat the water with concentrated chlorine.


We mentioned in Method 1 that sulfate-reducing bacteria (SRB) are the principal culprits why your hot water stinks. These microorganisms multiply aggressively in low-oxygen and hot environments, producing hydrogen sulfide gas.

Treating the water tank with concentrated chlorine should kill these microorganisms.

  1. Disconnect the water heater from its water and power (gas or electricity) supply.
  2. Open the water heater drain valve and drain about five gallons.
  3. Open the storage tank’s water outlet and pour up to a gallon of chlorine bleach into it.
  4. Connect the water line to the heater outlet port.
  5. Open several hot water faucets and allow the water to run.
  6. Close all hot water fixtures once you smell chlorine coming out instead of a musty sulfur odor.
  7. Leave the chlorine solution in the water heater for a full day.
  8. Reopen the hot water fixtures the next day and observe the water’s odor for a chlorine scent.
  9. Reestablish gas supply (or electrical power) to the water heater if you no longer smell chlorine.

Safety Tip: Please avoid using hot water for at least 24 hours to help remove the concentrated chlorine from the system.

Method 3. Consider treating the water if you have a contaminated source.


If chlorination doesn’t eliminate odor from your other water fixtures, there’s a good chance you have a contaminated water supply. Please note this only occurs if you get water from a well or other “untreated” water sources.

Although you can buy a water heater odor killer kit, it might be ineffective in solving the issue with your other appliances. Hence, we recommend the following tricks.

  • Install a de-chlorinating filter. You should install this system after the main water supply valve to remove chlorine taste and odor (CTO) before the water reaches the heater and other fixtures.
  • Set up a hydrogen peroxide filter. Installing a hydrogen peroxide filter is similar to dechlorinating filter installation. This product is much safer than chemical cleaners and doesn’t create any harmful by-products.
  • Use a backwashing filter. This system eliminates hydrogen sulfide by forcing the water back into a large tank and through a filter bed. Unfortunately, it only works with slightly alkaline water (i.e., pH 8.0 or more).
  • Consider aeration systems. This solution isn’t for DIYers because aeration systems are case-dependent. A professional plumber can assist you in such instances.

Method 4. Drain, flush, and disinfect the hot water tank.


This method should clear the sulfur smell from water tank units as part of routine maintenance (i.e., every six months). You can observe the following procedures.

  1. Disconnect the heater from its power or fuel source.
  2. Open a nearby hot water fixture to replace the hot water in the tank with cold water. Alternatively, you can leave the water heater overnight to cool.
  3. Turn off the valve supplying water to the water heater.
  4. Connect a flexible hose to the water heater drain valve and extend the other end to a garden or floor drain.
  5. Open a hot water faucet before turning on the drain valve.
  6. Empty the water from the tank.
  7. Allow cold water to enter the tank, and begin flushing by opening the cold water supply valve.
  8. Continue flushing until you don’t see debris and other impurities in the water.
  9. Close the drain valve, add concentrated chlorine, and follow the steps outlined in Method 2.
  10. Refill the hot water tank if the water no longer smells like poop or chlorine.
  11. Reestablish power or fuel supply.

Method 5. Replace the anode rod with zinc or aluminum versions.


Hydrogen sulfide buildup can also result from an interaction between a water heater’s water and the anode rod, especially if the latter’s the magnesium type. Replacing the anode cylinder with a zinc or aluminum unit should address the smelly issue. Here’s how.

  1. Read the owner’s manual for specific instructions on anode removal and replacement.
  2. Cut off the water heater’s power (or fuel) and water supply.
  3. Drain about half of the water heater’s contents.
  4. Remove the water heater’s topmost access panel or cover.
  5. Unfasten the magnesium anode using a ratchet with a 1-1/16-inch-deep socket.
  6. Slowly lift the magnesium anode out of the water heater and discard it.
  7. Get the zinc or aluminum anode replacement and wrap silicone or Teflon tape around its thread.
  8. Insert the zinc or aluminum anode into the water heater and tighten it with the socket and ratchet wrench.
  9. Reestablish water and power (or fuel) supply.

Causes of Sulfur Smell in Hot Water Heaters


You have a better chance of sulfur odor removal success if you know the common causes.

  • Uncontrolled growth of sulfate-reducing bacteria (SRB) due to leftover water in the storage tank
  • Contaminated water source (i.e., deep wells)
  • A chemical reaction between sulfide compounds and magnesium anode rods, increasing hydrogen sulfide levels
  • Increased SRB levels in salt-based water softeners

Preventive Measures to Avoid Sulfur Smell in the Future


Preventing unpleasant sulfur odors from the water heater requires addressing the common causes described above.

Installing a whole-house water filtration system (preferably one that eliminates hydrogen sulfide, sulfur, and other unwanted chemicals) can prevent this smelly issue. Activated carbon filters are excellent choices for low levels of hydrogen sulfide (under 1 mg/L).

Subjecting the water heater to aeration, ozonation, oxidizing media filtration, and continuous chlorination also helps.

Replacing the anode with a powdered version (i.e., insoluble titanium) can be a better solution than aluminum or zinc anode replacement.


We showed you five proven ways on how to remove sulfur smell from hot water heater units.

Although these methods are effective, we recommend hiring a professional plumber to examine your water-heating system if the problem persists or you need assistance with any of these tricks.

Moreover, a professional can help you diagnose the issue and recommend a more appropriate solution while considering the circumstances and factors surrounding the problem. It will make your hot water experience more pleasant.

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