Appearance Drain flies (also known as sink or moth flies) are short, hairy insects with wings that give them a moth-like appearance. There are more than 4,700 species worldwide. Most are native to humid tropics. Drain flies are usually around 4-5 mm long and are shaped like a long, thick, flattened cylinder. Habitat The larvae live in aquatic or sludge-based habitats, including bathroom sinks where they feed on bacteria and can become a problem. They can also be found in kitchen or basement walls and are more active at night. Prevention Drain flies can become an issue if they start to multiply -- this will usually happen if you have a clogged drain or excess moisture where they start to breed. If you have plumbing issues in the home right away to avoid any type of drain fly infestation. If the infestation has already occurred, call your Critter Control of Seattle expert today for control and prevention! 206.317.5048 Critter Control of Seattle Service Area Algona, Auburn, Beaux Arts Village, Bellevue, Black Diamond, Bonney Lake, Bothell, Brier, Buckley, Burien, Carnation, Clyde Hill, Covington, Darrington, Des Moines, Dupont, Duvall, Edgewood, Edmonds, Enumclaw, Everett, Fall City, Federal Way, Fife, Fircrest, Gig Harbor, Hunts Point, Issaquah, Kenmore, Kent, Kirkland, Lake Forest Park, Lakewood, Lynnwood, Maple Valley, Medina, Mercer Island, Mill Creek, Milton, Mountlake Terrace, Mukilteo, Newcastle, Normandy Park, North Bend, Pacific, Preston, Puyallup, Ravensdale, Redmond, Renton, Ruston, Sammamish, Seatac, Seattle, Shoreline, Snoqualmie, South Hill, South Prairie, Steilacoom, Sumner, Tacoma, Tukwila, University Place, Woodinville, Woodway, Yarrow Point, King County, Pierce County. This franchise is independently owned and operated by Awrylo Enterprises, Inc. dba Critter Control of Seattle. Licensed, bonded, and insured.