6 Weird Smells In Your House And How To Prevent Them

As summer approaches, you may be looking forward to hosting gatherings and enjoying time with family and friends (especially if you checked everything off of your spring home maintenance checklist)—the last thing you want is a house filled with weird smells.

But unpleasant odors can be more than just an unfortunate nuisance. Sometimes, weird smells in the house can be early warning signs of underlying problems that could lead to bigger issues down the road.

Taking the time to identify and address the source of these smells now can prevent them from becoming a nuisance and, more importantly, stop small problems from turning into costly repairs.

Before you send out those invitations, here are some common smells you may be experiencing and how to tackle them.

1. Fishy Odor

A fishy odor wafting through your house may seem harmlessly unpleasant, but you shouldn't ignore it. This smell can have a surprising culprit: electrical issues.

When electrical components like wires or outlets overheat, the burning plastic insulation can emit a distinct fishy odor, which you shouldn't take lightly. It indicates potential overheating that could lead to electrical fires.

Common locations:

• Walls near light switches or outlets
• Around electrical panels, typically located in garages or basements.
• In the vicinity of appliances that have recently been overworked or are breaking down

Level of urgency: High

Actions to take:

• Turn off and unplug any appliances that were recently in use
• Do not use any outlets or switches that feel warm to the touch.
• Call a qualified electrician to diagnose the problem and make repairs. Don't attempt to fix electrical issues yourself.

Preventative measures:

• Plug in fewer appliances at once to help avoid overloading or overheating your circuits.
• Have your electrical system inspected annually, especially if your home is older.
• Replace any worn-out outlets or switches, as using outdated or damaged outlets and switches can increase the risk of electrical fires and other hazards.
• Unplug appliances when not in use to prevent overheating, such as toasters, space heaters, and irons.

2. Sewage

Sewage smells are unmistakable and unpleasant. In addition to putting a damper on summer entertaining, they could signal a potential problem with your plumbing system.

Sewage smells can range from moderate to high urgency issues, depending on the problem. While sewage smells could indicate backed-up plumbing, strong sewage odors could indicate a larger problem that you shouldn’t ignore.

Methane is one of the main gasses in sewage, and a build-up can become flammable or leak into your home, posing a serious health risk. This build-up can occur due to several plumbing issues, including:

• Leaking or cracked pipes: Damaged pipes can allow sewer gas to escape into your living space.
• Blocked air vents: Vent pipes are crucial for venting sewer gasses safely out of your home. Blockages in these vents can trap the gas indoors.
• Clogged drains: Severe clogs can prevent proper ventilation and lead to a build-up of sewer gas.
• Dry P-traps: The U-shaped pipe under sinks and drains (the P-trap) holds water to create a barrier between sewer gases and your home. If this water evaporates due to infrequent use, sewer gas can seep back up.

Common locations:

• Bathrooms, especially around the toilet or shower drain
• Kitchen drains
• Floor drains in basements or laundry rooms
• Around vent pipes on the roof or exterior of the house

Level of urgency: Moderate to high

Actions to take:

• Identify the source of the smell by checking drains for clogs, inspecting for leaks around pipes or toilets, and ensuring vent pipes are clear.
• If you're comfortable with DIY plumbing maintenance, cleaning a sink’s drain trap could address the issue. Unscrew the slip nuts holding the trap in place, empty the trap, clean any debris, and reassemble the trap with fresh washers to help ensure a tight seal.
• Run plenty of water down affected drains to flush out any debris.
• For persistent smells or leaks, call a licensed plumber to diagnose and repair the issue.

Preventative measures:

• Avoid pouring grease or food scraps down drains.
• Regularly pour boiling water down drains to prevent grease buildup.
• Have your sewer line inspected and cleaned professionally every few years.

3. Ammonia

While some cleaning products contain ammonia, a lingering ammonia smell that isn't cleaning-related could indicate a couple of issues. A strong ammonia smell near your refrigerator could indicate a leak in the coolant lines or defrost pan. This is a high-urgency issue, as a refrigerant leak can damage the appliance and potentially cause a fire hazard.

Washing machine hoses can also deteriorate over time, causing a leak that releases ammonia from the cleaning products used. A strong ammonia smell in crawl spaces or behind walls could also indicate a decomposing rodent or small animal, which you should take care of promptly to avoid attracting pests and creating unsanitary conditions.

Common locations:

• Kitchens near refrigerators or freezers
• Utility rooms or laundry rooms near washing machines
• Around floor drains
• Bathrooms near drains or toilets (although less common)
• Behind sheetrock
• Inside crawl spaces where small animals could get in

Level of urgency: High

Actions to take:

• Check for leaks around refrigerator coolant lines or defrost pans. Consider a smart home upgrade, like a water leak detector, to get alerts to leak issues to help prevent them from becoming a bigger problem.
• You can also manually inspect washing machine hoses and connections for leaks. Look for signs of animal decomposition (e.g., dead rodent) near floor drains or crawl spaces.
• Turn off and unplug any appliances suspected of leaking.
• Open windows and doors to ventilate the area.
• For strong ammonia smells or suspected leaks, call a qualified professional.

Preventative measures:

• Inspect washing machine hoses for cracks or wear and tear, and replace them when necessary.
• Maintain proper ventilation in crawl spaces and around floor drains.
• Seal any gaps or holes around pipes that could allow rodents to enter your home.
• Replace washing machine hoses every 5-7 years.

4. Rotten eggs

A rotten egg smell is one of the most concerning odors you might encounter in your home. This unpleasant scent is known to be an indicator of a gas leak, commonly caused by natural gas, propane, or hydrogen sulfide. Ignoring this smell can pose serious risks, including fire hazards and health issues due to gas inhalation.

Common locations:

• Around gas appliances like stoves, water heaters, or furnaces
• Near gas pipelines or connections
• In poorly ventilated areas or crawl spaces

Level of urgency: High

Actions to take:

• Evacuate the house immediately and take everyone (including pets) outside to fresh air. Leave the doors and windows open while you wait for the gas company to arrive.
• Immediately call your gas company or a qualified technician to inspect and repair the gas leak.
• Do not turn on or off any electrical devices, switches, or appliances, as they can ignite the gas.
• Turn off the main gas valve to your house if you can locate it safely. The valve is usually near the meter outside your house.

Preventative measures:

• Regularly have your gas appliances serviced by a qualified technician.
• Install carbon monoxide detectors in your home and test them monthly.
• Avoid using a gas oven or stove for space heating.

5. Damp or musty

A persistent damp or musty odor in your house can be unpleasant and might signal a problem with moisture control. This smell is often associated with mildew growth, a relative of mold that thrives in damp environments. Leaky pipes, roofs, or air conditioners can all create excess humidity and lead to overly damp environments.

While a musty smell in the house isn’t immediately harmful, ignoring the smell can lead to the spread of mildew and mold spores that could cause allergies or respiratory issues. Luckily, getting rid of mold or mildew isn’t hard to do if you spot it early.

Common locations:

• Basements
• Attics
• Bathrooms (around showers or tubs)
• Kitchens (around sinks or under appliances)
• Closets
• Areas with poor ventilation

Level of urgency: Low to moderate

Actions to take:

• Locate the source of moisture or water intrusion that is causing the dampness and musty smell. Look for leaks around pipes, windows, or the roof. Check for condensation on walls or pipes.
• Increase airflow by opening windows, using exhaust fans, or installing a dehumidifier to reduce humidity.
• Repair leaky pipes, roofs, or faucets.
• For small areas of mold or mildew, mix a solution of water and white vinegar and scrub the affected area. For extensive and clearly visible mildew growth, consult a professional remediation company.
• Regularly inspect and maintain your home's plumbing, HVAC system, and roof to prevent water damage and moisture buildup.
• Consider mold insurance, but review your home insurance policy to understand which types of mold issues are covered.

Preventative measures:

• Use exhaust fans in bathrooms and kitchens when in use. Open windows to allow fresh air circulation, especially after showering or cooking.
• Dry damp surfaces promptly. Don't let wet towels or clothes pile up. Wipe down condensation on walls or windows.
• Regularly check around pipes, faucets, windows, and the roof for signs of moisture buildup.

6. Sweet smell

A sweet smell in your home might seem pleasant, but it can indicate a serious issue, like a coolant leak from appliances like refrigerators, air conditioners, or heat pumps. Both air conditioners and refrigerators rely on coolant to function. If there's a leak in the coolant lines, it can emit a sweet smell. Coolant can be toxic if inhaled or ingested, so promptly addressing a leak is important.

Inhaling or ingesting coolant chemicals can not only be harmful to your health, but they could also damage your appliances if they aren’t fixed.

The urgency depends on the location and strength of the smell. A faint sweetness near a refrigerator might be a lower-urgency concern, but a strong, syrupy odor near your air conditioner could be a high-urgency issue.

Common locations:

• Around air conditioning units or refrigerators
• Near heat pumps
• Under sinks or near cabinets (if there's a leak behind them)

Level of urgency: Low to moderate

Actions to take:

• If you suspect a coolant leak, turn off your air conditioner or refrigerator at the breaker box outside your home. Also, check for visible leaks around the appliances or under cabinets.
• Do not touch or inhale the coolant chemicals, and avoid consuming any food or drinks that may have been exposed.
• Don’t attempt to fix suspected coolant leaks yourself. Call a qualified HVAC technician to diagnose the leak and make repairs.

Preventative measures:

• Schedule regular maintenance for your air conditioner and refrigerator.
• Inspect for leaks around these appliances periodically.