Description
Drain flies are common, frequently-abundant insects also known as moth flies. Adult drain flies are tiny (1/5 to 1/6 inch long), fuzzy and grayish insects with the body and wings covered with hairs. The source of the fly infestation is generally from sinks and floor drains, or from nearby sewage plants or waste disposal areas. They are weak fliers and are often seen hovering about drains/sinks during the evening hours.

Habitat
Adult flies usually congregate at windows, darken lamp shades at night, fall into food and accumulate around bathtubs, showers, sinks and floor drains, especially in the basement/crawlspaces. These flies breed in areas such as, the sides of drains and overflow pipes in homes, or in sewage disposal beds, septic tanks and moist compost. They have also been found in dirty garbage containers, rain barrels and tree holes.

Life Cycle
Eggs are deposited throughout the spring and summer in moist, decomposing organic materials. The gelatinous organic deposits, which accumulate in drains, provide an ideal breeding site. Eggs hatch into the maggots, which feed in this organic matter. Under favorable conditions, maggots mature in about two weeks and form a hard shell within which the pupa forms and from which the adult fly emerges.

Health Concerns
Bronchial asthma can be caused by inhaling fragments from dead flies. Since Drain flies breed in filthy conditions, there is the possibility of disease transmission.

Control
One of the best measures in controlling drain flies is cleaning sinks, drain pipes, and traps with a stiff wire brush or by steam. Several new products are now available that contain either bacteria or enzymes which breakdown the gelatinous scum in drains. They are applied as either a pour around the drain lip or injected as foam.  ArmaXX Pest Control provides this as a service. To determine which drain is infested, place a jar over the outlet or tape a plastic bag over the opening of the overflow outlet. Check the container at intervals for adult flies.