How to get rid of drain flies at home and prevent them from returning

Scrubbing drains, using enzyme-based cleaners and eliminating standing water can help get rid of drain flies at home and prevent them from returning.

"These are little filth flies that live in the gelatinous slime that can build up in drain pipes," Southern Living quoted Faith Oi, PhD, as saying. "You'll often see them hanging out in areas such as near kitchen or bathroom drains."

Drain fly larvae develop in the sludge formed by food scraps and other organic debris accumulating inside drainage pipes, Oi said.

The insects can also breed in other damp locations, including areas affected by sewer or septic leaks, dirty garbage bins, rain barrels, air-conditioner drainage outlets, refrigerator drip pans, tree holes and abandoned bird nests.

Although drain flies are not known to transmit diseases or bite people or pets, their presence can indicate unsanitary conditions that should be addressed rather than ignored.

Experts recommend several measures to eliminate these pests and prevent them from returning.

Scrub away buildup inside drains

The first step is to physically remove the slime coating the inside of drainpipes. Oi recommends using a stiff drain brush or drain snake to scrub the interior surfaces, paying particular attention to ridges and crevices where sludge accumulates.

Thorough cleaning helps remove the organic material that supports the insects, along with any eggs and larvae developing inside the pipes.

Use enzyme-based drain cleaners

Once visible blockages have been cleared, an enzyme-based drain cleaner can help break down remaining organic residue.

Eliot Moakes, owner and pest control technician at Pest Control Leicester, recommends first removing obstructions with a long, narrow drain snake before applying the cleaner. "You need to keep drains clean and flowing properly, deal with standing water and regularly run water through drains that aren't used very often," Good Housekeeping quoted him as saying.

Keeping pipes free of buildup and ensuring proper drainage makes them less suitable breeding sites for drain flies.

Eliminate standing water and moisture

Drain flies can reproduce wherever stagnant water and decaying organic matter collect.

Households should regularly inspect drains, garbage containers, air-conditioner condensate outlets and other moisture-prone areas for potential breeding sites.

Drains that are rarely used should also be flushed with water regularly to prevent buildup and maintain proper drainage.

Avoid unproven home remedies

Although essential oils and ultrasonic pest-repellent devices are sometimes promoted as solutions, Oi says there is no scientific evidence that they can effectively dissolve drain sludge or prevent drain fly infestations.

Removing the breeding material is more important than simply trying to repel or kill the adult insects.

Seek professional help if the problem persists

If drain flies continue appearing despite thorough cleaning, the infestation may originate from damaged plumbing, hidden leaks or other moisture problems.

In such cases, a plumber or pest control professional can help locate and address the underlying source.