The best way to eliminate pesky drain flies, also known as moth flies, is to remove all traces of organic film within the drain with an industrial strength enzymatic drain cleaner and hard bristle brush. Organic drain cleaners eliminate biological matter that supports drain fly larvae. Clean any drains where adult flies have been spotted. If the sink has a J trap, that needs cleaning as well.Continue Reading
Identifying decaying organic material within the drain pipe is critical to managing an infestation. Adult flies remain close to their breeding site. They can breed in more than one spot. Drains can be inspected by removing the drain plate and scraping the sides of the drain with a dull knife that reaches at least 6 inches deep. Pouring hot water or bleach down the drain temporarily kills flies, but this does not remove organic matter on which larvae thrive.
Sometimes drain fly larvae are located deeper within the pipe, notes University of California Statewide Integrated Pest Management Program. In these instances, cleaning the drain to remove larvae requires a drain snake or the services of an expert plumber. If the breeding site is within a wall or other unexposed area, consult with a professional pest removal service.Learn more about Pest Control