Drain Cleaning & Unclogging
Open clogged sinks, tubs, laundry lines and main drains, and find out why they keep stopping.
Plumbing guide
Drain Flies in Goodyear, AZ: Where They Breed and Fixes
Furry little flies that bob around a sink, tub or floor drain nearly always hatch inside the pipe. Killing adults changes little until the sludge feeding the larvae is removed.
By the Goodyear Express Plumbing team ·
What drain flies are
Drain flies, sometimes called moth flies, are tiny gray or tan insects with hairy wings that rest in a roof shape when still. They flutter in short hops instead of flying straight. They do not bite, and their presence does not mean the house is dirty. It means a drain somewhere holds a layer of organic film that the larvae feed on.
A female lays eggs in that film, and the cycle repeats in a couple of weeks when the weather is warm. Valley homes stay warm nearly year round, so a small problem can grow quickly if nobody interrupts it.
Confirm which drain it is
Before cleaning anything, find the source. In the evening, lay a strip of clear tape sticky side down across each suspect drain, or set a small cup upside down over it with a thin smear of petroleum jelly on the rim. Check in the morning. The drain that caught flies is your breeding site.
Check the rarely used places too: a guest bathroom shower, a floor drain in the garage or laundry room, a utility sink and the overflow hole in a bathroom sink. People tend to look at the kitchen and miss a tub that nobody has run for months.
Why bleach and boiling water disappoint
Pouring bleach down a drain sends it past the film in seconds. It does not scrub the upper walls of the pipe or the underside of the drain flange, where larvae sit. Boiling water may kill what it touches, yet it leaves the buildup in place and is hard on older plastic fittings.
The reliable fix is mechanical. Remove the stopper or strainer, scrub the pipe wall with a stiff drain brush, rinse, and repeat for several days. Enzyme or bacterial cleaners made for drains can help digest what remains, provided you use them as the label directs.
Telling small flies apart
Three tiny insects get confused. Where you find them is the best hint.
| Insect | Appearance | Found near | Remedy |
|---|---|---|---|
| Drain fly | Furry body, wings folded like a roof | Sink, tub and floor drains | Scrub the sludge off the pipe wall |
| Fruit fly | Tan body with red eyes | Produce, garbage and open cups | Take away the food and wash the bin |
| Fungus gnat | Slender, dark, slow flier | Potted plants kept too wet | Let the soil dry out |
Floor drains and dry traps
Every drain has a curved section called a trap that holds a plug of water. That water blocks sewer air from entering the room. In a floor drain that is rarely used, the water can evaporate, and Arizona heat makes that happen faster than many people expect.
Pour a quart of water into seldom used drains once a month. A spoonful of cooking oil on top slows evaporation. If the room smells even with a full trap, the problem may sit deeper in the line. Our guide to sewer camera inspection explains how a plumber looks inside it.
When cleaning at home is not enough
Sometimes a thick film lines a long section of pipe that a brush cannot reach. A plumber can scrub the line with a cable machine, or use hydro jetting to wash the full pipe wall. Routine drain cleaning also makes sense when a drain is slow, gurgles or smells.
If flies appear along with slow drains in several fixtures, treat that as a sign the main line may be partly blocked. Mention it when you call so the right tools are sent.
Habits that keep them away
Run water in every sink, tub and shower at least weekly. Clean pop-up stoppers, where hair and soap collect. Grind a few ice cubes in the disposal to loosen residue, and keep the dishwasher and air conditioner condensate lines clear because both stay damp.
Fix slow leaks under sinks, since a constant damp spot feeds the same insects. Seal gaps around pipes where they enter walls. A small fan in a damp utility room also helps.
Tell them apart from other small flies
Fruit flies are tan with red eyes and gather around ripe produce, trash and open drinks. Fungus gnats are slim and dark and hover around overwatered houseplants. Drain flies are fuzzy and rest on walls close to the drain. Treating the wrong insect wastes weeks, so use the table below before you buy any spray.
A weekly routine for stubborn cases
Pick one evening a week and work through every drain in the house in the same order. Pull the stopper, scrub the visible pipe, rinse with hot tap water and replace the stopper. Keep the same order each time so a missed drain stands out.
Track what you find in a note on your phone. If one drain keeps collecting flies after three cleanings, the film may sit beyond your reach, and that drain deserves a professional cable or jetting pass. Quiet seasons are a good time, because summer heat and monsoon humidity both help the flies breed faster.
Natural and chemical aids
Enzyme cleaners made for drains digest organic matter and are gentle on pipes. Follow the directions, usually applying them at night when the drain is not used. Avoid mixing products.
A bacterial drain treatment works slowly but keeps film from rebuilding. Use it monthly in problem drains.
When flies keep returning
Return visits point to a source you have not found. Check for a leaking pipe behind a cabinet, a damp wall, a slow condensate line and a floor drain in a hidden closet. A plumber with a camera can see inside the line.
See sewer camera inspection for what a camera finds.
Common questions
Drain fly questions
They do not bite and are mostly a nuisance. They can carry bacteria on their bodies, so removing the source is better than ignoring them.
Once the film is scrubbed out, adults die off within a couple of weeks. Repeat the cleaning for several days to catch new larvae.
Not usually. If scrubbing does not help and you smell sewage or have slow drains in several places, a camera inspection can check the line.
Sprays kill adults but do nothing for larvae in the pipe, so the flies return. Clean the drain itself.
Related services
Hydro Jetting
Wash grease, scale and roots from pipe walls with high pressure water where a cable falls short.
Sewer Camera Inspection
Look inside the sewer pipe on video before a repair or a home purchase.
More plumbing guides
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Roots follow moisture into old joints. Learn the signs and the repair paths from cutting to replacement.
Drains smelling or clogging again?
Phone in with what you notice and the dispatcher will line up a nearby contractor.