Key Points
- A rotten egg smell in water is almost always caused by hydrogen sulfide gas — a byproduct of anaerobic bacteria reacting with your water heater’s anode rods.
- The smell is most common in water heaters that have sat unused, and it worsens when magnesium or aluminum anode rods are present.
- A fishy or sewage-like smell points to different causes: algal blooms, chemical contamination, or organic buildup in drain pipes.
- A bleach smell means excess chlorine — common in homes supplied by reservoirs that require higher disinfectant levels during transport.
- If your water smells like gasoline, stop using it and call your water company immediately — this is a health emergency.
You turn on the faucet and the smell hits you before the water does. That sulfur odor coming from your tap is one of the most common water quality complaints homeowners in Duncanville and the surrounding area call us about — and the good news is, it is almost always fixable.
Why Does My Water Smell Funny?
If a homeowner finds that their water smells like rotten eggs, it means a substance near the water is present in such high concentrations that a human can detect an odor. Contamination doesn’t mean that the water is unsafe to drink, but bad smelling water is so off-putting that people find it intolerable.
People will quickly arrange for a plumber to get to the bottom of the problem and drink bottled water in the meantime. Here are some ways water can smell bad and why:
Water Smells Like Rotten Eggs
A common complaint is that the water smells like rotten eggs. This usually means that there’s an excess of sulfur in the water in the form of hydrogen sulfide. A sulfur smell in water is most likely caused by the home’s water heater, especially after sitting unused for a long time. This is a problem if the heater is in a vacation home and is turned off before the homeowner leaves.
The sulfur smell in water happens when anaerobic bacteria in the heater’s water interact with the tank’s anodes. These anodes, which are often made of aluminum and magnesium, are in the tank to attract minerals that would otherwise build up on the heater’s necessary components and shorten its life. But when the anodes are attacked by anaerobic bacteria, which live in an oxygen-free environment, hydrogen sulfide gas is a byproduct.
The human nose is especially sensitive to the smell of hydrogen sulfide gas. The person will detect a musty odor at deficient levels, but the rotten egg smell comes when the concentration rises to at least 1 part per million.
If flushing the water heater or replacing the anode rod does not resolve the smell, the issue may require a professional assessment. Our team at Benjamin Franklin Plumbing of Duncanville offers water heater repair service backed by upfront pricing and master-licensed plumbers — William McDaniel M-17631 and David Crow M-38221. We serve Duncanville, Cedar Hill, DeSoto, Glenn Heights, Waxahachie, Midlothian, and surrounding Southwest Dallas communities.
How to Fix a Rotten Egg Smell in Your Water Heater
There are three common remedies for hydrogen sulfide in a water heater. First, flush the tank completely to remove stagnant water and sediment. Second, raise the water heater temperature to 140°F for several hours to kill anaerobic bacteria — then lower it back to 120°F to prevent scalding. Third, replace the magnesium anode rod with a zinc-aluminum rod, which produces far less hydrogen sulfide. If the smell persists after all three steps, contact a licensed plumber for a full diagnostic.
Water That Smells Like Fish
A variety of substances can give water a fishy smell. The water can smell that way because of harmful algal blooms, also called HABS, but chloramines, barium, or cadmium can cause it. Chloramine is a compound formed when an amount of ammonia gets into the water supply and reacts with chlorine.
Barium and cadmium are metals. Barium can infiltrate plumbing pipes and private wells if the property is near a mineral ore that contains the metal. Cadmium is found in the waste product or as a byproduct of chemical fertilizer. These substances can give the water a fishy smell, and if their levels are high enough, they can also be quite toxic.
Like the rotten egg smell, the human nose is sensitive to even small amounts of the compounds that cause an algal bloom’s fishy smell. Algal blooms are overgrowths of algae that appear in bodies of water, including reservoirs. They usually occur in the summer.
If the water isn’t cleaned before it comes into the home, some algae can contaminate it and cause a fishy smell. Water that has algae in it can also smell mildewy or musty from compounds such as 2-methylisoborneol or geosmin.
The smell may be incredibly intense in the late summer when the algae start to die. Like cadmium, barium, and chloramine, algal blooms can be toxic, and the homeowner should contact their water company if they think algae is causing a fishy smell.
For homeowners dealing with consistently off-tasting or off-smelling water, a whole-home water filtration system or a water conditioning solution can remove many of these contaminants at the point of entry, before the water ever reaches your tap.
Water That Smells of Sewage
Water that reeks of sewage is probably picking that smell up from the drain and plumbing pipes. This smell signifies that organic material has been caught in the drain pipes and attacked, as the anodes in the water heater, by bacteria.
The byproduct is sewer gas, which can be detected when the faucet is turned on, and the gas is pushed up and expelled. Interestingly, the water doesn’t contain the smell. If a glass of water is taken some distance away from the sink and sniffed, there’s no smell.
Though the bad smells from the pipes and bad smells from the water heater seem different, both are caused mainly by hydrogen sulfide.
Water That Smells Like Bleach
If a homeowner smells bleach in their water, it’s a sign that it has an excess of chlorine. Chlorine, which is a rather nasty gas in its pure form, is a crucial disinfectant. It kills pathogens and parasites and is often used to shock well water.
This is one reason why plumbers suggest that a homeowner let their faucets run for a while after they’ve shocked their wells. Though it can be used in strengths as high as 4 milligrams per liter, humans can smell chlorine at much lower levels.
Homeowners may also detect a chlorine smell if their water has to be pumped in from a long distance. Maintaining a remote reservoir might add a bit more chlorine to keep the water clean as it travels.
Persistent chlorine or chemical taste in your water is a strong indicator that a water softener system or whole-home filtration could meaningfully improve your water quality — and protect your pipes from the long-term effects of mineral buildup.
Water That Smells Like Gasoline
It is unusual for water to smell like gasoline, but it needs to be tended to as soon as possible. The presence of gasoline in the water can cause serious health problems. The homeowner should call their water company and the department of health in their area right away if they notice a gasoline smell in the water. The smell might be caused by a leaking fuel tank, leaking landfills, or runoff from a farm that’s gotten into the water supply.
Frequently Asked Questions About Smelly Water
Is water that smells like rotten eggs safe to drink?
In most cases, yes — hydrogen sulfide at low concentrations is not considered a health hazard. However, the smell is a strong indicator of bacterial activity in your water heater or pipes, which should be addressed. If your water smells like rotten eggs and tastes different than usual, stop drinking it until a plumber has assessed the source.
Can I fix a rotten egg smell in my water myself?
Some fixes — like flushing the water heater or replacing an anode rod — are manageable DIY tasks. However, if the smell comes back quickly or affects cold water as well as hot, the source may be in your municipal supply or well, which requires professional water quality testing.
What if my whole house smells like sulfur, not just the water?
A whole-house sulfur smell that is not limited to running water can indicate a sewer gas or gas line issue. Do not ignore this. Call a licensed plumber immediately.
Benjamin Franklin Plumbing of Duncanville serves Cedar Hill, Dallas, DeSoto, Duncanville, Glenn Heights, Grand Prairie, Maypearl, Midlothian, Oak Cliff, Oak Leaf, Ovilla, Red Oak, and Waxahachie. Whether you need water heater service, a filtration system, or just a straight answer about your water quality, we show up on time — or it’s you we pay. Contact our team today to schedule a visit.
