Drain flies, also called moth flies or sewer gnats, are a common but often misidentified pest in Bellingham bathrooms, basements, and commercial kitchens. They breed in the gelatinous organic film that lines slow or infrequently used drains, and Whatcom County’s older homes and floor drains give them plenty of habitat. Sasquatch Pest Control finds and eliminates the breeding sites most people overlook, backed by a 100% service guarantee and no long-term contracts.

How to Identify Drain Flies

Drain flies are small, about 2 to 5 mm long, with a fuzzy, moth-like appearance and a soft gray to tan body and wings covered in fine hairs that give them a powdery look. At rest they hold their wings over the body in a roof-like shape. They are weak, hopping fliers rather than strong ones, and you almost always find them sitting on walls and ceilings near sinks, showers, floor drains, and sewage areas.

Signs of a Drain Fly Problem

The main sign is small fuzzy flies resting on walls and ceilings around drains, showers, tubs, floor drains, and basement sumps, most active in the evening. You may notice more of them near a seldom-used bathroom or a floor drain that has dried out. A simple test is to tape a clear cup or plastic loosely over a suspect drain overnight; adults emerging and getting trapped confirm that drain as a breeding site.

How Sasquatch Treats Drain Flies in Whatcom County

Sasquatch inspects to pinpoint which drains and moist organic buildup are producing the flies, since surface sprays alone never fix a drain fly problem. We mechanically clean and treat the affected drains to remove the biofilm where larvae develop, address the underlying moisture or plumbing issues, and knock down adults. We confirm the source is eliminated and back the work with our 100% guarantee and free return visits.

How to Prevent Drain Flies

Keep drains flowing and clean by periodically scrubbing them with a stiff brush and flushing away the organic slime that larvae feed on. Run water in guest bathrooms, floor drains, and rarely used fixtures so the traps do not dry out, fix leaks and standing-water problems, and repair damp areas in basements and crawlspaces. Avoid pouring grease down drains, since it feeds the buildup that drain flies breed in.

Frequently Asked Questions

What are drain flies and where do they breed?

Drain flies, also called moth flies or sewer gnats, are small fuzzy flies that breed in the gelatinous organic film coating the inside of drains, traps, and pipes. Larvae feed on that slime, so the breeding sites are almost always inside slow-moving or infrequently used drains.

How do I know which drain the flies are coming from?

Loosely tape a clear cup or a piece of plastic over each suspect drain overnight. If adult flies appear trapped underneath the next morning, that drain is a breeding site. Checking each drain this way pinpoints exactly where treatment is needed.

Will bleach get rid of drain flies?

Not reliably. Bleach mostly runs straight through and does not remove the clingy biofilm on the pipe walls where larvae live. Physically scrubbing and treating the drain to strip out that organic layer is what actually works, which is why professional treatment is more dependable.

Are drain flies harmful to my health?

They do not bite or sting and are not known to transmit disease to people, but because they breed in sewage and organic filth they can mechanically carry bacteria, and large numbers are an unsanitary nuisance, particularly in kitchens and food-handling areas.

How much does drain fly treatment cost in Bellingham?

It depends on how many drains are involved, the severity of the buildup, and any plumbing or moisture issues behind it, so we provide a free, upfront quote after inspecting. There are no contracts, and every treatment is backed by our 100% service guarantee.