Why Is There a Strange Cabbage Smell in My House?

By HomeSmitten Team · · Updated

Why Is There a Strange Cabbage Smell in My House?

The quick answer

A cabbage smell with no cabbage cooking is a sulfur smell. Treat a strong or unexplained one as a possible gas leak: leave, then call your gas company or 911 from outside. If you rule that out, the usual causes are a dry or dirty drain (sewer gas), rotting food or trash, a water heater that makes sulfur smell in hot water only, or damp and mold. Most of these are fixable in an afternoon.

People describe the same sulfur compounds as rotten eggs, cabbage, sewage or boiled vegetables. That's the stake: the smell can come from a harmless drain problem, or it can be the warning smell that utilities add to natural gas. You can't tell by nose alone, so the order of checks matters. Start with safety, then work through the everyday causes. For the full list of household smells and how urgent each is, see strange smells in the house.

Rule Out Gas First

Natural gas has no smell of its own. Connecticut's utility regulator says gas companies add mercaptan, which gives it a rotten egg smell. Washington Gas describes it as sulfur or rotten eggs. Neither mentions cabbage, but cabbage and rotten eggs are both sulfur smells, and Poison Control says a strong sulfur or rotten egg smell is a sign of a possible gas leak. Our judgment: if the smell is strong or has no explanation, act as if it could be gas.

If the smell is strong or you're unsure, leave the building and call your gas company from outside or from a neighbor's home. Don't flip light switches, use electrical equipment, use a phone inside, or light matches. Poison Control also lists a hissing or whistling sound from an appliance and bubbles in standing water as signs of a leak. Don't go back in until the gas company says it's safe. Washington Gas notes that not every suspected gas odor is a real leak, but only trained crews can say so.

Carbon monoxide is different: it has no smell at all. The Consumer Product Safety Commission says to get outside and call 911 if you suspect poisoning, and to keep CO alarms on every level and outside sleeping areas.

Sewer Gas and Drains

This is the most common real cause once gas is ruled out. Sewer gas contains hydrogen sulfide, which the CDC says smells like rotten eggs. It lists municipal sewers among the common sources. Every sink, shower, tub and floor drain has a curved pipe, the trap, that holds water and blocks that gas. The South Davis Sewer District says the water can evaporate when a drain goes unused, especially in hot or dry weather or in a vacant building, and then gas can enter the room.

Why would a house smell like cabbage?

The district's fix has three steps:

  • Pour a cup or two of water into seldom-used drains, such as a guest bathroom, a basement floor drain or a spare tub.
  • Run water through every sink, shower and floor drain at least once a month so the traps stay full.
  • For a longer seal, add a few ounces of mineral oil after the water. It floats on top and slows evaporation. The district recommends mineral oil over cooking oil, which can go rancid.

If the smell continues, the district says the trap may be damaged, a vent may be blocked, or there may be a leak, and a licensed plumber should diagnose it. Our judgment: smell each drain in turn, starting with the ones you use least. The smell is usually strongest at the culprit.

One safety note on drains. The CDC says high levels of hydrogen sulfide can knock out your sense of smell, so a smell that fades isn't proof the gas is gone. Typical household levels are not likely to cause health effects, according to the CDC, but don't stay in a room with a very strong, worsening smell. Don't mix cleaning products in a drain: the CDC lists misuse of drain cleaners among household sources of hydrogen sulfide, and Poison Control warns that bleach mixed with ammonia or acids makes toxic gas.

Food, Trash and Cooking Residue

Cabbage, broccoli, cauliflower and similar vegetables give off a strong sulfur smell as they cook and as they rot. Poison Control lists rotten food, mold, leaky drains and pet odors as common sources of bad smells at home. If the smell is strongest in the kitchen, check these, in this order (our judgment):

  • The trash can and the compost bin. Empty and wash them with detergent and hot water.
  • The crisper drawer and the back of the fridge. The FDA says to keep the fridge at or below 40°F, clean it regularly and wipe spills right away.
  • The pantry, under the sink and behind the fridge, where a forgotten bag of produce can rot.
  • The garbage disposal and sink drain, where a film of food builds up.

The FDA adds a useful rule: if you're not sure about food, throw it out, and you can't rely on odor or appearance to judge safety. After you clear out spoiled food, the same advice applies to your own cooking: run the range hood while you cook, and wash its filter, because oils hold the smell.

A Rotten Smell Only From the Hot Tap

If the smell comes from the water, test hot and cold taps separately. Penn State Extension says hydrogen sulfide gives water a rotten egg odor, and that a smell in hot water only may come from the water heater. The magnesium anode rod inside the tank can react with sulfates in the water to make hydrogen sulfide. Penn State says replacing it with an aluminum rod should stop the odor while still protecting the tank.

Don't take the rod out without advice. Penn State warns that removing it can increase corrosion and will likely void the heater's warranty. Ask a plumber or the heater maker which rod is right for your model. If the smell is in both hot and cold water, the cause is more likely in the supply. A city water utility can tell you about the public supply, and a well owner can test the water. Penn State notes that hydrogen sulfide in water is treated as an aesthetic problem because people notice it long before it reaches harmful levels, but it also says the gas is poisonous and flammable at high levels.

Damp and Mold

Mold usually smells musty, but a wet spot full of organic material can smell sulfurous. The EPA says to dry water-damaged areas and items within 24 to 48 hours, and to keep indoor humidity below 60 percent, ideally 30 to 50 percent. A moldy smell with no visible source can mean hidden mold behind drywall, wallpaper or paneling, or inside ductwork. The EPA says homeowners can often clean areas under about 10 square feet, and that larger areas, sewage-contaminated water or a contaminated HVAC system need a professional. If the HVAC system may be contaminated, the EPA says not to run it until you've checked.

Appliances That Hold Smells

A dishwasher can hold a sulfur smell. Samsung's support page says mold or mildew grows where there's moisture, warmth and food particles, and that the smell may come from the connected sink drain or garbage disposal. It says to remove and clean the filter if your model has one, clean the filter housing and drain area with warm soapy water, and clear clogged spray nozzle holes. If the smell stays, clean the sink drain or disposal, then call a plumber before cleaning the dishwasher again. Steps differ by brand, so check your manual.

Refrigerant and Furnace Leak Claims

Some pages blame cabbage smells on refrigerant or furnace leaks. I couldn't find an official source for either claim, so don't rely on them. A furnace that smells of gas, or of burning plastic or gunpowder, is a different matter: HVAC.com says to shut it off and call a technician, and says a rotten egg or sulfur smell can mean a gas leak, so leave and call your gas company.

Frequently Asked Questions

Is a cabbage smell in the house a gas leak?

It can be. Gas companies add a sulfur odorant, which they describe as rotten eggs, and cabbage is a sulfur smell too. If the smell is strong or unexplained, leave and call your gas company from outside.

Why does my bathroom smell like cabbage?

A dry drain trap is the most common cause. When water in the trap evaporates, sewer gas rises through the drain. Pour a cup or two of water into the drain, and run it monthly. If the smell stays, call a plumber.

Why does only my hot water smell like cabbage?

The magnesium anode rod in the water heater can react with sulfates in the water and make hydrogen sulfide. Ask a plumber about an aluminum replacement rod. Don't remove the rod, because that can speed up corrosion.

How do I get rid of a cabbage smell?

Find the source first. Empty and wash the trash can, clear out old food, refill unused drain traps, clean the dishwasher filter, and dry any damp areas within 24 to 48 hours. Ventilate while you work.

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