Flesh flies breed in dead animals, rotting meat, and decaying organic matter, so getting rid of them means finding and removing whatever they’re feeding on. Kill the adults you can see, but the infestation won’t stop until you eliminate the breeding source. The entire process, from locating the source to seeing the last adults die off, typically takes two to three weeks.
Confirm You’re Dealing With Flesh Flies
Flesh flies look a lot like common house flies, but there’s a reliable visual difference. Flesh flies have three black stripes running down the upper back of their body, while house flies have four. Flesh flies also tend to be slightly larger, around 3/8 inch long compared to the house fly’s 1/4 inch, and they have a more robust, hairy appearance. If you’re seeing large, grayish flies with three distinct dark stripes, you’re almost certainly dealing with flesh flies.
This distinction matters because it points you toward the right breeding source. House flies gravitate toward garbage and feces. Flesh flies are drawn specifically to dead tissue: animal carcasses, rotting meat scraps, or occasionally pet waste and decaying organic matter.
Find the Breeding Source
This is the single most important step. You can swat or spray every adult fly in sight, but if the source remains, new adults will keep emerging for weeks. Flesh flies deposit live larvae directly onto a food source (they don’t lay eggs like most flies), and those larvae feed for about four to five days before crawling away to pupate. Adults emerge 12 to 15 days after that. So a hidden carcass can produce waves of flies over several weeks.
If flesh flies suddenly appear indoors in large numbers, the most common culprit is a dead rodent or bird inside a wall void, false ceiling, or attic. Start by looking for wandering maggots. Flesh fly larvae leave the carcass when they’re ready to pupate, so you may find them crawling across floors, windowsills, or inside light fixtures. Trace the maggots’ path backward toward their source. If larvae are appearing in ceiling light fixtures, check the attic space directly above and inspect nearby wall voids.
Outdoors, check under and around dumpsters. Garbage that accumulates beneath a dumpster is one of the most common breeding sites for flesh flies near buildings. Also inspect compost bins, any area where pet waste collects, and shaded spots where a wild animal may have died.
Remove the Source and Clean Up
Once you find the carcass or decaying material, remove it completely. Bag it in a sealed plastic bag and dispose of it in an outdoor trash bin with a tight-fitting lid. If you find maggots in the surrounding soil (common under dumpsters or near outdoor drains), scrape them up along with the top layer of soil, seal everything in a plastic bag, and throw it away.
After removing the source, clean the area thoroughly. Wash hard surfaces with soap and water or a disinfectant to remove any residual organic material that could attract more flies. If the source was inside a wall and you had to open drywall to reach it, clean the cavity before sealing it back up.
For compost bins that are attracting flesh flies, the fix is raising the internal temperature. An efficient compost pile that reaches above 120°F will kill all immature fly stages. Turning the pile regularly and maintaining the right ratio of green to brown material helps hit that threshold. If your compost consistently runs cool, avoid adding meat scraps or animal products entirely.
Kill Adult Flies Indoors
While you wait for the breeding source cleanup to take effect, reduce the adult population inside your home. Fly light traps are effective for indoor use. These devices attract flies with ultraviolet light and capture them on a glue board. Place one or more depending on the size of the space, particularly near windows and in rooms where you’re seeing the most activity.
Sticky fly ribbons and standard fly paper also work for catching adults. They’re inexpensive and useful as a short-term measure while the source is being addressed. A simple fly swatter handles small numbers. Bug zappers are another option, though they’re better suited for garages, porches, and utility rooms than living spaces.
For surfaces where flies tend to land near entry points, you can apply a residual insecticide spray around door frames, window frames, and the exterior walls flanking doorways. This creates a contact barrier that kills flies resting on treated surfaces before they make it inside. Look for products labeled for outdoor perimeter use around homes.
Seal Entry Points
Flesh flies get inside through the same gaps and openings that let in every other pest. A systematic check of your home’s exterior can cut off their access.
- Doors: Install door sweeps or thresholds at the base of all exterior doors. Lie on the floor and check for light coming through underneath. Even a gap of 1/16 inch is enough for insects to enter. Pay special attention to the bottom corners, which are the most common entry point. Apply caulk along the bottom outside edge and sides of door thresholds. For garage doors, use a rubber bottom seal (vinyl becomes stiff and ineffective in cold weather). Sliding glass doors can be sealed by lining the bottom track with 1/2 to 3/4 inch foam weatherstripping.
- Windows and screens: Repair all gaps and tears in window and door screens. This is your primary defense against flies during warm months. Check screens for small holes that might seem insignificant but are large enough for a flesh fly to pass through.
- Utility openings: Seal gaps where pipes, wires, and vents enter the foundation and siding. This includes outdoor faucets, electrical receptacles, gas meters, dryer vents, and cable lines. Use silicone caulk, cement, expandable foam, steel wool, or copper mesh depending on the size and location of the gap.
- Attic and crawl space vents: Install 1/4-inch wire mesh (hardware cloth) over attic, roof, and crawl space vents. This prevents birds, rodents, bats, and squirrels from entering and dying inside your home, which eliminates one of the most common indoor flesh fly breeding sources.
For general crack and gap sealing, acrylic latex caulk is a good choice. It cleans up with water and can be painted over. Clear-drying caulk is more forgiving if your lines aren’t perfectly straight.
Manage Outdoor Attractants
Keeping flesh flies away from your property long-term comes down to sanitation. Garbage is the biggest draw. Use trash cans with tight-fitting, spring-loaded lids that close automatically. Empty outdoor bins at least once or twice a week, and always bag waste in sealed plastic liners before placing it in the can. If you have a dumpster, position it at least 50 feet from any door or window, and ideally downwind from your home so odors blow away from entry points rather than toward them.
Clean the area around and under dumpsters and trash cans regularly. Water used to rinse garbage bins can soak into the soil and create a secondary breeding site, so check these spots for maggots periodically. Clean outdoor drains in trash-handling areas to prevent organic matter from building up.
Pick up pet waste promptly. While flesh flies prefer carrion over feces, they will breed in animal waste when it’s available. If you keep livestock or have an agricultural setup nearby, manure should be removed weekly and disposed of away from your living area.
Timeline for Results
Flesh flies have a fast life cycle. From the moment larvae are deposited, they feed for about four to five days, pupate for 12 to 15 days, and then emerge as adults. The full lifespan of an adult can be as short as 15 to 21 days. This means that once you remove the breeding source, you may still see adults emerging from pupae that were already developing nearby. Expect a tapering off over two to three weeks rather than an immediate disappearance.
If new flies keep appearing after three weeks, you likely have a second breeding source you haven’t found yet. Repeat the inspection process, focusing on wall voids, attic spaces, and any outdoor areas you may have missed the first time.