How To Add Hydrogen Peroxide To A Water Heater (Do This!)

Upgraded Home Team
by Upgraded Home Team

Don’t be embarrassed; it happens to everyone! The infamous “rotten egg” smell is actually a common problem. If the hot water in your home has a sulfur stink, the problem could be bacteria build-up in your water heater.

Many people think that hot water kills bacteria. While that is true, the standing warm water in your home’s water heater will grow sulfate bacteria over time. Vacation homes and seasonal residences are especially susceptible due to irregular use.

To rid your hot water of bad odors, all you need is store-bought hydrogen peroxide. First, unplug the water heater and flip the circuit breaker off. When the water is cool enough, open the bottom valve and allow the tank to drain. Then, close the bottom valve and pour 1-2 pints of hydrogen peroxide into the water heater’s inlet pipe on top. Let the hydrogen peroxide work for 2-3 hours before flushing the tank and lines.

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Why Does My Water Smell Like Rotten Eggs?

Smelly water can be the result of a more serious problem (like a city or sewage issue), but it’s an easy DIY fix most of the time. Older houses supplied with well water are subject to naturally occurring elements like hydrogen sulfide and are commonly treated with chlorine. When not treated, well water can have a distinct smell. While harmless, the odor can make hot water unappealing to shower in, much less to drink.

If your home is not supplied by well water and your hot water smells like rotten eggs, you could be dealing with a build-up of sulfate bacteria within your tank. The bacteria develop when the water is left too long in the tank, operated at a low temperature, or turned off for an extended period of time.

Sulfate bacteria will also grow on your water heater’s anode rod, a temporary steel core that keeps the inside of your water heater from rusting. Such bacteria then feed on sulfur and produce hydrogen sulfide as waste.

What Is Hydrogen Sulfide?

Hydrogen sulfide is a toxic, corrosive, and flammable chemical compound. Even if most household water heaters do not have dangerous levels of hydrogen sulfide, it will quickly wear down your water heater when not addressed.

Sulfate bacteria in your water heater tank feed on sulfur, generating hydrogen sulfide gas as waste. When the gas dissolves in water, it reacts to create the rotten egg smell.

Adding Hydrogen Peroxide to a Water Heater

Tools You’ll Need

The tools you’ll need to incorporate hydrogen peroxide into your water heater maintenance will vary depending on what kind of water heater you use. To troubleshoot conventional storage-tank water heaters, you may only need hydrogen peroxide and a receptacle for the flushed water and sediment.

  • 1-3 bottles of 3% hydrogen peroxide
  • Bucket or hose for diverting water and sediment
  • Screwdriver
  • Crescent wrench
  • Drain valve attachment

Step One: Power Off

As with any electrical repair, make sure everything is powered off. If you are working with a gas water heater, turn the pilot light off. For an electric water heater, unplug the tank and flip the circuit breaker off.

Step Two: Turn On a Nearby Hot Tap

It can be anywhere– the laundry room, the bathroom, the kitchen– but pick a convenient location nearby and turn on the hot water tap on the sink. It may sputter but eventually, nothing should come out. Leave the tap opened in the on position. Opening another tap helps to speed up the draining process and prevents a vacuum from forming in the water heater.

Step Three: Drain The Water Heater

Once you’re sure the water in the tank has cooled, locate the valve on the bottom of the water heater tank. Turn left to open the valve. Drain the water into a bucket or feed to a hose that is diverted outside. When the water heater is drained, shut off the hot water tap on the sink.

Step Four: Add Hydrogen Peroxide

Add 1-2 pints of hydrogen peroxide per 40 gallons. Since most residential water heaters hold 40-60 gallons, a couple of bottles of store-bought hydrogen peroxide will do the trick. Add 3% hydrogen peroxide to the cold water inlet opening. Alternatively, you can utilize the T&P valve or hot water outlet. Turn on the cold water inlet momentarily and let the solution sit for 2-3 hours.

Step Five: Flush The Hydrogen Peroxide Solution

After the hydrogen peroxide has been working for a few hours, turn on the cold inlet valve again. While water fills the tank, turn on a nearby hot tap as well. Position a bucket beneath the bottom valve. Turn left to open the bottom valve to flush the bacteria out of your water heater. Collect any sediment in the bucket.

Step Six: Fill Tank

Once the water coming from the bottom valve is free of sediment, you have successfully flushed your water heater. Close both the bottom valve on the water heater and the hot water tap from your sink nearby. Fill the water tank. Turn off the cold inlet.

Step Seven: Power On

For electric water heaters, plug your device back into the wall and turn on the circuit breaker. For gas water heaters, adjust the setting back from pilot.

You should notice an immediate difference in your home’s hot water. The flush will have cleared out the hydrogen sulfide, the chemical compound that causes that “rotten egg” odor. Repeat the process about every year or as needed.

Safety Precautions

As with any electrical repair, the most crucial step is turning off the power. With electrical water heaters, make sure to unplug the tank and flip the circuit breaker. Improper water heater repair can lead to flooding, damaged drywall, even damaged furniture.

With gas water heaters, make sure the pilot light is off. When dealing with gas, an improper repair can lead to carbon monoxide leaks or a gas build-up– possibly even an explosion.

If your water heater is more than ten years old or is prone to water leaks, it may be time to replace your water heater. If your water heater is performing erratically, do not attempt to fix it yourself and contact a professional repair company.

Alternative Solutions

Adding hydrogen peroxide to your water heater is the easiest way to combat any unpleasant odors coming from your home’s hot water tap. If you are looking for a more permanent solution, there are a few alternatives that are proven to work.

Replace Magnesium Anode Rods with Aluminum

If your home has hard water, consider replacing your water heater’s magnesium anode rod with an aluminum rod. Anode rods are metal rods screwed to the top of the water heater that attract corrosive elements in the water. Since aluminum is less reactive than magnesium, aluminum will deteriorate more slowly. Your water heater’s sacrificial anode rod is essential, as the anode rod’s condition will determine the lifespan of your water heater.

Chlorine Injection

A chlorine injection system helps to break up and deflect iron bacteria and hydrogen sulfide by infusing chlorine into the water. When the chlorine reacts with the iron, the chlorine will oxidize and kill the bacteria. Chlorine injection is a popular treatment for homes that source their water from a well. Since the chlorine doses are precisely measured, it’s relatively easy to control the chlorine.

Aeration Tank

Since hydrogen sulfide is simply a gas in water, you can get rid of your water heater’s foul smell through an aeration process. Aeration pumps air into your water heater to oxidize and dissolve the hydrogen sulfide. This process promotes the growth of healthy microorganisms that feed on the iron bacteria and hydrogen sulfide.

Maintaining Your Water Heater

Many water heaters come with 12-year warranties yet often need to be replaced before the ten-year mark. On the other hand, it’s not unheard of for a water heater to last thirty years when properly maintained.

A water heater tank is essentially a large metal tub filled with water. We know that water rusts metal and causes it to decay. The sacrificial anode rod– true to its name– is a magnesium or aluminum rod that “sacrifices” itself by attracting the corrosive minerals in the water to the anode rod instead of the steel water tank.

To lengthen the life of your water heater, it is important to replace the anode rod every two years. If your home has hard water, you may need to replace the anode rod more frequently.

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Related Questions

Is sulfur water safe to drink?

While foul-smelling water may not be pleasant, most residential water heaters don’t carry dangerous levels of sulfate bacteria. Low levels of sulfate bacteria in your water can affect the taste and smell. High levels of sulfate bacteria in your water can induce diarrhea, dehydration, and other gastrointestinal issues.

How often should I flush out my water heater?

Water heater manufacturers suggest flushing your water heater every six months to a year. If your home has hard water, you may need to flush your heater more often. At the very least, experts recommend draining one gallon from the drain valve each month.

What happens if I don’t maintain my water heater?

Sediment can build-up and form a mineral “mud” in the bottom of your water heater tank. As the water temperature rises in the tank, minerals in the water create sediment particles that come to rest on the bottom of the water heater. If your water heater goes untreated long enough, the sediment will begin to affect the appliance’s efficiency. You may experience higher energy bills and varying water temperatures. In extreme cases, sediment buildup can clog the T&P valves and cause an explosion.

Upgraded Home Team
Upgraded Home Team

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