Dead Rat Smell in the Wall | Find It, Clear It, Stop It

Few household smells are worse. It shows up suddenly, gets stronger for a few days and seems to come from inside the wall. If you’ve had rats in the attic, or someone put out poison recently, a dead rat smell in the wall is the most likely cause. Here’s how to confirm it, find it and get rid of it.

Is It Really a Dead Rat?

A dead rodent smell has a few telltale signs:

• Sweet and rotten, not musty like mold or sharp like urine
• Strongest in one area, often near a wall, closet, ceiling corner or cabinet
• Gets worse for a few days, then slowly fades
• Flies gathering at a window, light fixture or outlet in that room
• A small stain on drywall or a ceiling below the spot
• Pets sniffing or staring at the same section of wall

Other smells can be confused with it, like a gas leak or a sewer line. If you smell rotten eggs or think it could be gas, leave the house and call the gas company right away.

How Long Does Dead Rat Smell Last?

It depends on the size of the rodent, the temperature and how much air moves through the space. A mouse in a cool wall may fade within a week or so. A rat in a warm attic or a closed wall cavity can smell for several weeks. Air fresheners only mask it for a while. Removing the carcass is the only way to end it quickly.

How to Find a Dead Rat in the Wall

1. Follow your nose. Walk the room and the rooms on either side, and note where the smell is strongest, including high and low on the wall.
2. Check above and below. Look in the attic over that spot and in the crawl space or garage below. Rodents often die near where they were traveling.
3. Watch for flies. They lead you to the closest point to the carcass.
4. Look for stains or dampness on drywall or ceilings.
5. Think about their routes. Spots near plumbing, AC lines and attic access are common.
6. Call for help before cutting. A professional can often find it with a small inspection camera through an outlet or tiny hole, so only one small access cut is needed, if any.

Getting the Dead Rat Out

• From the attic or crawl space: if you can reach it, remove it with gloves and a sealed plastic bag, and keep kids and pets away.
• From inside a wall: a small access hole, often near the baseboard or behind a cabinet, is usually all it takes. It can be patched and painted afterward.
• From a ceiling: reaching it from the attic above is usually easier than cutting the ceiling from below.
• Under the house or behind appliances: check behind the fridge, dishwasher and water heater, and along the foundation vents.

If you’re not comfortable opening a wall or crawling into a tight space, this is the part to hand off.

How to Get Rid of Dead Rat Smell

1. Remove the carcass and any nesting material. The smell won’t fully go away while it’s still there.
2. Treat the spot. Use an enzyme cleaner or odor neutralizer made for organic odors on the surface where it lay.
3. Replace what can’t be cleaned. Soiled insulation or stained drywall may need to come out.
4. Air out the space. Open windows and run fans to move fresh air through the room.
5. Give it a few days. Leftover odor usually fades once the source is gone.

Clean Up Safely

Dead rodents, droppings and nesting can carry germs. Wear gloves and a mask. Spray the area with disinfectant and let it soak before wiping. Don’t sweep or vacuum droppings dry. Bag everything, seal it and put it in an outdoor trash bin, then wash your hands well.

How to Stop It Happening Again

A dead rat in the wall means a live entry point somewhere. To keep it from happening again:

• Skip the poison. Most anticoagulant baits are restricted in California, and poison is a common reason a rat dies inside a wall. See Is Rat Poison Legal in California?
• Trap instead. Traps placed along the runways catch rats where you can remove them.
• Seal the gaps. Close the openings at the roofline, vents, pipes and foundation with metal mesh and sealant. Our Rodent Exclusion page explains how.
• Check for others. If one rat died inside, others may still be living in the attic or walls.