A sulfur or "rotten egg" smell coming only from your hot water is almost always caused by hydrogen sulfide gas. This happens when naturally occurring sulfates in your water supply interact with a degrading magnesium anode rod, creating a warm, ideal environment for harmless but smelly sulfur bacteria.
To get rid of a sulfur or "rotten egg" smell in your hot water, flush the heater and sanitize it with about a quart of 3% hydrogen peroxide. If the smell returns, replace the standard sacrificial anode rod with an aluminum/zinc or powered titanium rod.
A rotten egg smell from a water heater is caused by hydrogen sulfide gas. It is generally not dangerous or toxic in the concentrations found in household water, but it is a major nuisance that can stain metals and makes the water highly unpleasant.
Bathing or showering in water with a sulfur odor is not directly harmful, and the absorption of hydrogen sulfide through the skin during bathing is generally considered to be minor.
To remove the sulfur (rotten egg) smell from your water, you must first determine if it affects both hot and cold water, or just the hot water. The treatment depends on the source of the odor.
In most cases, a sulfur smell in water is not dangerous. The "rotten egg" odor comes from hydrogen sulfide gas, which is detectable at extremely low levels. While it is unpleasant, it is generally considered an aesthetic nuisance rather than a severe health risk.
The absolute cheapest way to remove sulfur (the rotten egg smell) is degassing. Because sulfur gas is volatile, you can simply let a glass of water sit overnight so the air oxidizes the sulfur, or you can install an aeration system directly in your well for around $115 to spray and vent the gas.
One of the easiest ways to detect it is by smell—black mold emits a strong, musty odor often compared to rotting plants, damp paper, or cedar wood. If you're unsure whether you're detecting mold, ask someone with a “fresh nose” to confirm, as you may have become desensitized to the smell in your home.
Hot Water Supply
The bacteria in the water heater are not a health threat; however, they must be eliminated to stop the odor problem. You should consult your owner's manual or contact a licensed plumber.
To tackle the dreaded "rotten egg" sulfur (hydrogen sulfide) smell in your shower, you need a filter specifically packed with KDF-55 (Kinetic Degradation Fluxion) or Catalytic Carbon. These materials neutralize sulfur gas and heavy metals upon contact.
It's from bacteria in your water heater producing H2S gas. You might get away with running your water heater hotter to kill the bacteria (worth flushing the tank as well to get any solids out), or you may have to shock chlorinate it.
No, standard household white vinegar will not damage your hot water heater. In fact, it is widely recommended by plumbers as a safe, natural way to flush out mineral buildup.
No, carbon monoxide (CO) is a completely odorless, tasteless, and colorless gas.
Water containing hydrogen sulfide usually does not pose a health risk, but does give water a nuisance "rotten egg" smell and taste. Water supplies with as little as 1 ppm (part per million) hydrogen sulfide are corrosive and may tarnish copper and silverware.
A strong sulfur smell under the hood is often the battery. Test your fuel system. If it's an over-rich fuel mixture to blame, it can appear like a bad catalytic converter. However, testing your fuel pressure and looking at the spark plugs to look for excessive fuel can help identify this.
To test water for bacteria, use a do-it-yourself (DIY) home kit for rapid results or send a sample to a state-certified laboratory for maximum accuracy. Testing for coliform and E. coli bacteria identifies contamination from animal or human waste.
Neutralizing a sulfur smell (often resembling rotten eggs) depends on the source. The best approach is to neutralize the specific chemical compounds, like hydrogen sulfide, causing the odor.
It is more effective than chlorine for treating iron and sulfur. For hydrogen sulfide (rotten egg smell), hydrogen peroxide oxidizes the sulfide compounds, breaking them down into sulfur particles that can then be filtered out. It works faster than chlorine at eliminating sulfur odors.
Yes, you can filter sulfur and its foul "rotten egg" odor out of water. Because sulfur is usually present as dissolved hydrogen sulfide gas, standard filters (like basic pitcher filters) aren't enough. You will need one of these targeted methods:
However, there are still risks worth paying attention to: Taste and odor: Even if it's not harmful, sulfur water makes drinking, cooking, and cleaning less appealing. Plumbing damage: Hydrogen sulfide can corrode metal pipes, fixtures, and appliances, leading to costly repairs.
The characteristic "old age smell" is scientifically known as nonenal (or 2-nonenal). It is a chemical compound produced when the skin's natural oils and fatty acids break down and oxidize as we age.
Disinfect and flush the water heater with a chlorine bleach solution. Chlorination can kill sulfur bacteria. If all bacteria are not destroyed by chlorination, the problem may return within a few weeks. Increase the water heater temperature to 160 degrees Fahrenheit (71 degrees Celsius) for several hours.
No, standard Brita filters are not certified or designed to remove sulfur or hydrogen sulfide (the gas that causes the "rotten egg" smell) from drinking water.
Many dermatologists do recommend shower filters, especially for people with sensitive skin, eczema, or dry hair. Chlorine and other chemicals in tap water can strip natural oils from skin and hair, leading to dryness and irritation. A shower filter can help reduce exposure to these chemicals and minimize irritation.
Ordinary household water softeners do not remove sulfur odors from water.