You think you smell something fishy — even though you haven’t cooked anything resembling salmon or swordfish in days.

Or maybe it’s the smell of your fireplace — even though you haven’t set fire to a log in weeks. Or the odor resembles ammonia, rotten eggs or something else entirely.

Such household odors can serve as clues that there are hidden dangers in the home – problems that could be pricier to repair and potentially hazardous to your health if not found and fixed fast.

Here’s what homeowners need to know about eight home odors:

Power strip with plastic melted and fire sparked and smoke emitting to illustrate a fishy smell in the home
A fishy smell could be a sign of an electrical problem. (Mikhail Dmitriev via

1. Fishy Smell That’s Not Fish

Some people refer to this as a urine or burning rubber smell. This could be something electrical in the home overheating and melting its insulating plastic or ­rubber — which could lead to a fire.

The most likely culprit is an appliance, such as a dishwasher, washing machine or air conditioner. Sniff near each of these while they are running to try to identify the source.

When you think you have found the source, either call in a repair professional to investigate… or replace the appliance if it is approaching the end of its useful life.

Warning: If the odor seems to be emanating from a wall switch, outlet or some other part of your home’s electrical wiring, not an appliance, switch off the circuit breaker and call an ­electrician.

Common house mouse looks out from a mink in the wall
If you detect an ammonia smell in your home, it could be a sign of a dead mouse. ©Irina K./ Adobe Stock

2. Ammonia Smell That’s Not Ammonia

Some people describe this as the smell of death, and they’re right — a mouse or some other small animal likely has died inside your home.

One solution is to find and remove the corpse, and that’s often easier said than done — there’s a good chance that it is in a hard-to-reach spot inside your walls, ceiling or floor.

Use your nose to find where the smell is strongest, and search everywhere you can in that area. Consider buying and using a small snaking digital inspection camera to peek into walls, behind cabinets and appliances and into other tight spots.

Ridgid Hand-Held inspection cameras are a good choice, starting at less than $150. Unfortunately, even with a snaking camera, you won’t be able to see everywhere without drilling holes in walls, and that usually causes more problems than it solves.

Of course, you could just wait for the smell to go away, which typically takes a few weeks. Meanwhile, inspect the perimeter of your home for gaps where rodents can enter, and seal these to prevent further invasions.

Also, deploy rodent traps — not rodent poison — in the home. If you use poison, additional rodents might die in their hard-to-reach nests inside your home, creating more bad smell.

Danny Lipford sprays antimicrobial spray onto water damaged wood subfloor to kill mold growth and eliminate musty odor
Using an antimicrobial spray can effectively eliminate musty odors caused by water leaks by killing the mold and bacteria that contribute to the smell. (3 Echoes Content Studio)

3. Damp, Musty Smell

This usually signals mold or mildew, which could become a big problem for both your home and your health if not quickly remedied. Certain types of mold and mildew can also produce a fishy smell.

Use a digital ­hygrometer to check the relative humidity of each room in the house. You can find these for less than $10 online or at home-improvement stores.

If you get readings above 50 percent, run a dehumidifier. Apply an antimicrobial spray to carpets, curtains and fabric-covered furniture in any room that has high humidity and/or a musty odor.

Meanwhile, search these rooms for water leaks. Look behind refrigerators and under sinks for wet spots. Visit the room during the next hard rain to look for visible leaks.

Go down to the basement, crawl space or room directly beneath this musty room to look for evidence of water leaks there, too — those could point to leaks that are hard to spot in the room above.

Read: Mold Removal: When to DIY the Job or Hire A Pro

Brick fireplace with dirty bricks in firebox
If you detect a musty or smoky odor from your fireplace that is not in use, it could be due to a buildup of creosote. (AEvenson via

4. Musty/Smoky Odor From a Fireplace That’s Not In Use

First, make sure that the chimney dampers are closed. Chimney smells can be drawn into the house when these are left open.

If that’s not the problem, vacuum and then scrub the “firebox” — the area that contains the fire at the base of the chimney.

If the smell persists after the firebox has dried following this cleaning, call in a chimney sweep to clean and inspect your chimney. Mention that you suspect water might be getting in.

The problem might be as simple as a dislodged chimney cap, or there might be cracks in the masonry. Make sure the chimney sweep checks whether the damper is sealing ­sufficiently.

You can purchase and use an inflatable damper, sometimes called a fireplace draft stopper. These are available for less than $100.

Listen: Ask Danny | Ep. 11: Keeping a Chimney in Tip-Top Shape

Furniture assembly parts and tools for self assembly
The smell that comes from pressed-board furniture, also known as particleboard or MDF, is caused by the formaldehyde-based adhesives used in its production. (Evgeniia Medvedeva via

5. Chemical Smell From New Furniture, Carpet or Paint

A fresh coat of paint, a new piece of pressed-board furniture or a new carpet can off-gas volatile organic compounds (VOCs) that are not just unpleasant to smell but also unhealthy to breathe.

When possible, remove new pressed-wood furniture and carpeting from its packaging and let it air out in your garage for at least an hour, and preferably overnight, before bringing it into your home.

If that isn’t feasible, open all the windows in the room and run fans to circulate the air for at least an hour and as long as a full day. That method also works when you are painting interior walls.

Tub drain with hard water stain
A sewage smell coming from a bathtub drain can indicate a problem with the plumbing system, such as a clog or backup. (skhoward via

6. Sewage Smell

This sometimes is confused with the rotten-egg smell, but it’s less “eggy” and more like the smell of an outhouse or a portable toilet.

It probably is coming from a drain. Use your nose to determine which one — it could be the drain of a toilet, sink, tub or shower.

One possibility is that there isn’t enough water in this drain’s “P trap.” The P trap is a curved piece of pipe below the drain that should be full of water — the water blocks offensive odors from your sewer line or septic tank from wafting back into the house.

If this is the case, running the water for a few seconds (or flushing the toilet) should solve the problem. You also will have to air out the house to get rid of the odor that’s already there. This is especially likely if the toilet, sink, tub or shower has gone unused for months — the water in the P trap might have evaporated.

If that does not solve the problem — or if you see that the water is not draining properly — the odor probably is coming from material clogged in the drain line.

Put on rubber gloves, and use a flexible 16-to-18-inch drain-cleaning brush to clear out any gunk from the drain.

Next, let the hot water run for a few minutes (or flush the toilet) to confirm that it is now draining properly.

Then shut off the water and pour one cup of bleach into the drain. Let the bleach sit for 30 to 60 minutes, then run the hot water (or flush the toilet) again.

If the odor persists, you may need to rent or purchase a plumber’s auger or snake to dislodge the clog. (Keep in mind a clogged drain or a sewage backup can also produce a fishy smell.)

Natural gas meter on the side of a brick home
A rotten-egg smell in a home can indicate a gas leak, which is caused by the presence of sulfur in natural gas and can be a serious safety hazard that requires immediate attention. (PhilAugustavo via

7. Rotten-Egg Smell (Gas Leak)

A rotten-egg smell might be a potentially dangerous natural gas leak. Get everyone out of the house — leaving the door and windows open so that some gas can escape — and call your gas company immediately to report the problem and request further instructions.

Natural gas itself is odorless, but a sulfur-like rotten-egg smell is added so that leaks will be detected.

Residential water heater and circuit breaker box
Draining a water heater can resolve the issue of a rotten-egg smell in water, also known as sulfur water. (JulNichols via

8. Rotten-Egg Smell (Sulfur in the Water)

If a faint rotten-egg smell occurs only when your hot water is running, however, it’s probably not a gas leak at all but rather a small amount of odorous sulfur in the water.

Sometimes you or a plumber can solve this problem by shutting off the water line leading to the water heater, using a hose to drain the tank, then refilling the tank.

Portions of this article originally appeared on Bottom Line Inc.

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Editorial Contributors
Danny Lipford

Danny Lipford


Danny Lipford is a home improvement expert and television personality who started his remodeling business, Lipford Construction, at the age of 21 in Mobile, Alabama. He gained national recognition as the host of the nationally syndicated television show, Today's Homeowner with Danny Lipford, which started as a small cable show in Mobile. Danny's expertise in home improvement has also led him to be a contributor to popular magazines and websites and the go-to source for advice on everything related to the home. He has made over 200 national television appearances and served as the home improvement expert for CBS's The Early Show and The Weather Channel for over a decade. Danny is also the founder of 3 Echoes Content Studio,, and Checking In With Chelsea, a décor and lifestyle blog.

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