Common houseflies are not only an annoyance, they are also a health concern. Houseflies feed on waste, and they pick up bacteria as they feed. North Carolina University explains that houseflies are linked to the spread of more than 30 diseases. Most of these diseases aren't transmitted on a regular basis, but the possibility of housefly-induced illness exists, and you should exterminate flies as soon as possible. With the right methods, you can get rid of existing fly populations and prevent new houseflies from invading your home.
Things You'll Need
Place sticky traps around your home. The Texas A&M Agrilife Extension recommends 10-inches of flypaper per 1,000 cubic feet of space.
Hang a UV-trap in your home. These traps are commonly called bug zappers.
Keep doors and windows closed, and repair any faulty exterior seals. Good weatherstripping keeps houseflies at bay.
Spray a sugar-based insecticide around your home.
Clean your house regularly. Flies feed on waste and lay eggs in garbage.
Parasitic wasps and ants feed on flies and don't harm humans. This option isn't always practical, since you may not want to introduce more bugs into the house. However, if you prefer biological controls, parasitic wasp and ant breeds work relatively well.