Why does my water smell like rotten eggs?

12/09/2022 Stephen Tamlin

Key facts: 

• If your water smells like rotten eggs it is likely caused by hydrogen sulfide gas
• Although in most instances your water will be perfectly safe to drink, a rotten egg smell can be a sign of dangerous water contamination
• There are several ways you can locate and remove the problem

Have you noticed your water smells like rotton eggs?

If your tap water smells like rotten eggs, the odor is usually caused by the levels of sulfur bacteria and hydrogen sulfide gas that can be found in a building’s water supply. If you only experience the smell when using your hot tap, it may be a chemical reaction occurring inside your hot water heater, and not a problem with your water supply. 

You may be surprised to know that there are up to 50 chemicals added to Australia's water supplies for a variety of purification and health purposes. For many people it can be a common problem to have strange odors coming from their tap water, especially if the supply comes from a well or still source.

Potential Problems with Hydrogen Sulfide

If you have hydrogen sulfide in your water supply, the main reason your hot water can smell like rotten eggs, it can damage pipes as it corrodes many different types of metals and can also cause black stains on silverware and plumbing fixtures. In most cases drinking water that has a strong rotten egg odor, although particularly unpleasant, is perfectly safe to drink. However in some rare occasions the odor may be caused by sewage or other contaminates in a building’s water supply, which could cause health problems.

What Causes The Smell?

If your water smells like rotten eggs, the odor is usually caused by the levels of sulfur bacteria and Hydrogen Sulfide that can be found in a building’s water supply. If you only experience the smell when using your hot tap, it may be a chemical reaction occurring inside your hot water heater, and not a problem with your water supply.

What Should You Do if you Smell Rotten Eggs?

If you do experience any new odors it is always important to find the source of the problem by checking taps and water supplies around the building.

• If your hot water smells like rotten eggs, it is likely because of your water heater. Contact a trained boiler inspector to see how this can be fixed.
• If your cold water also smells like rotten eggs, but only from the water treated by a water softener and not in the untreated water, the problem is likely to be sulfur bacteria in the water softener. Changing the water softener solution will solve this issue.
• If the smell is strong when the water in both the hot and cold faucets is first turned on, and it diminishes or goes away after the water has run, or if the smell varies through time the problem is likely to be sulfur bacteria in the well or distribution system. This could also be a sign that there is a more dangerous problem in your water supply.

• If the smell is strong when both the hot and cold faucets are first turned on, the problem is likely hydrogen sulphide in the groundwater. This could also be a sign that there is a more dangerous problem you’re your water supply.

If you are concerned about what is in your water you can purchase test kits that will check the levels of hydrogen sulfide, sulfate, sulfur bacteria, and iron bacteria.

Improving Your Drinking Water

One of the better alternatives to drinking straight from the tap is using a water filter that eradicates harmful contaminants. At Waterlogic, our mission is to deliver fresh, clean water to all offices across Australia. Our Firewall™ filtration water coolers eliminate 99.9999% of bacteria found in tap water sources. Take a look at our product line or request your quote for a water cooler.