To treat a sewer drain for flies, pour hot water down the drain to kill any existing flies and thoroughly clean the drain pipes and traps. To clean scum out of the pipes, pour salt and baking soda down the drain and chase it with vinegar or add a commercial drain-cleaning product to the drain.Continue Reading
Drain flies are also known as moth flies, and they tend to breed in scummy drains. To remove flies from a sewer drain, run through the following steps.
Hot water can help kill any existing flies.
Thoroughly clean out drain traps with a wire brush and steam. Clean out any sinks running into the sewer.
Clear the upper portion of the drainpipe with a wire brush. Clean scum out of the rest of the pipe with baking soda cleaner or a commercial cleaner. To try an at-home cleaner, pour a half-cup of baking soda and a half cup of salt down the drain. Add a half cup of vinegar and leave the mixture to foam for one minute. Pour two quarts of boiling water down the drain. To use a commercial product, choose a product that contains enzymes or bacteria to break down the scum, and follow the product's directions.
Regularly pouring hot water down the drain prevents scum from building up.