Tiny, fuzzy insects fluttering around your sink or shower drain are a common but annoying household pest. These are drain flies, also known as sewer flies or moth flies. They are breeding in the slimy buildup inside your pipes. To get rid of drain gnats, you must eliminate the organic film that feeds their larvae, not just swat the flying adults.
The simple answer to how do I get rid of drain flies is to thoroughly clean the inside walls of your pipes. This guide provides the professional plumbing steps and products needed for complete drain fly removal tips that work better than any bug spray. We will show you exactly how to kill the larvae and prevent future infestations.
What Are Drain Flies?
Drain flies are small, non-biting insects often seen resting near bathroom and kitchen drains. They are sometimes called moth flies because their hairy bodies and wings give them a fuzzy, moth-like look. They are very weak fliers and rarely travel far from their breeding site.
These flies do not look for human food. They look for standing water and the thick layer of organic matter, called biofilm, that coats the inside of plumbing pipes. This biofilm is a mix of soap scum, grease, hair, and other decaying materials. The larvae live inside this slime, protected and well-fed, until they emerge as adult flies. The entire life cycle takes about three weeks. You must break this cycle to achieve lasting results.
Drain Flies vs. Fruit Flies
People often mix up drain flies and fruit flies, but they’re different pests that need different solutions.
Drain flies have fuzzy wings and bodies. They look like tiny moths. You’ll find them near sinks, showers, and floor drains. They fly in short, jerky patterns and often rest on walls near drains.
Fruit flies are smaller and smoother. They have red eyes and tan bodies. These bugs hang around ripe fruit, garbage cans, and anything sweet or fermenting. They fly in quick, darting movements.
The key difference? Drain flies breed in drains. Fruit flies breed in rotting food. If you see fuzzy flies near your bathroom or kitchen sink, you’re dealing with drain flies.
How to Know if You Have Drain Flies
Spotting a few flies doesn’t confirm you have drain flies. Here’s how to check:
The Tape Test works best. Before bed, dry the inside of your drain with a towel. Place clear tape over the drain opening, sticky side down. Leave it overnight. Check the tape in the morning. If you see small flies stuck to it, you’ve found their breeding spot.
You can also look for these signs:
- Small flies resting on bathroom or kitchen walls
- Fuzzy-looking insects near drains or pipes
- Flies that seem weak or slow (they’re not strong fliers)
- More activity in the evening when drain flies are most active
Check every drain in your home. Drain flies can breed in shower drains, sink drains, basement floor drains, and even washing machine drains. The tape test helps you find exactly where they’re breeding.
Why Drain Flies Come Into Homes
Drain flies don’t just appear randomly. They’re attracted to specific conditions in your plumbing.
Organic buildup is the main draw. Hair, soap scum, food particles, and grease create a slimy layer inside pipes. This slime feeds bacteria, which drain fly larvae. The thicker the buildup, the better the breeding ground.
Moisture keeps the slime wet and hospitable. Drains that get regular use stay damp enough for drain flies to thrive. Even small leaks under sinks can create breeding spots.
Cracks and gaps let adult flies enter. Broken pipe seals, loose drain covers, and cracks in basement floors give them access to breeding areas.
Rarely used drains are especially prone to drain fly problems. Guest bathroom sinks, basement floor drains, and outdoor spigots can develop thick slime layers when water doesn’t flow regularly to wash buildup away.
How to Get Rid of Drain Flies
Getting rid of drain gnats requires attacking their breeding grounds. Killing adult flies won’t solve the problem because new ones keep hatching. Follow these steps for effective drain fly removal tips.
Step 1: Identify All Affected Drains
Use the tape test on every drain in your home. Mark which drains show flies. You need to treat all breeding sites or the problem continues.
Step 2: Clean Drains Thoroughly
This is the most important step for drain flies treatment. You need to remove the slime where they breed.
For accessible drains:
- Remove the drain cover and stopper
- Use a drain brush or pipe brush to scrub the sides
- Reach as far down as you can to break up slime
- Rinse with hot water
Boiling water method:
- Boil a full kettle of water
- Pour it slowly down the drain
- Wait 5 minutes
- Repeat 2-3 times
- Do this daily for one week
The hot water kills larvae and loosens slime. But it won’t remove all the buildup by itself.
Baking soda and vinegar treatment:
- Pour 1/2 cup baking soda down the drain
- Add 1/2 cup white vinegar
- Let it fizz for 30 minutes
- Flush with hot water
- Repeat every few days
This method breaks down organic matter naturally.
Step 3: Use Enzymatic Drain Cleaners
These products eat away the organic slime. Look for gel-based enzyme cleaners made specifically for drain flies. Follow the product directions carefully. Most require overnight treatment.
Apply the cleaner before bed so it can work while the drain isn’t being used. Regular drain cleaners with harsh chemicals don’t work well because they don’t target the slime layer effectively.
Step 4: Kill Remaining Adults
While you’re treating the drains, reduce the adult population:
- Use a fly swatter for quick kills
- Set up apple cider vinegar traps near affected drains
- Spray adults with soapy water (dish soap and water in a spray bottle)
Vinegar trap method:
- Fill a small bowl with apple cider vinegar
- Add 2 drops of dish soap
- Place it near the drain
- Flies are attracted to vinegar and drown in the mixture
Step 5: Repeat Treatments
Drain fly eggs and larvae can survive initial treatments. You need to repeat cleaning for at least one week. This breaks the life cycle and prevents new adults from emerging.
Clean affected drains daily with hot water. Use enzyme cleaners twice during the week. Continue until you don’t catch any flies on the tape test for three consecutive days.
You can read about: How to Get Rid of Springtails in Bathroom
How to Stop Drain Flies From Returning
Once you eliminate drain flies, keep them away with these habits:
Weekly maintenance:
- Flush drains with hot water once per week
- Pour boiling water down rarely used drains
- Run water in guest bathrooms regularly
Monthly deep cleaning:
- Scrub drains with a brush
- Use enzyme cleaner in all drains
- Check under sinks for leaks
Good daily habits:
- Don’t let standing water sit in sinks
- Clean sink stoppers regularly
- Wipe down sink areas to prevent buildup
- Use drain screens to catch hair and debris
Fix problem areas:
- Repair leaking pipes promptly
- Seal cracks around drains
- Install drain covers that fit tightly
- Address moisture issues in basements
For drains you rarely use, run water through them at least once a week. This prevents slime buildup and keeps the p-trap filled, which blocks sewer gases and pests.
When to Call a Professional
Most drain fly problems clear up with consistent home treatment. But sometimes you need expert help.
Call a plumber if:
- Treatments don’t work after two weeks
- You suspect broken or damaged pipes
- Drains stay clogged despite cleaning
- You find flies but can’t locate the breeding source
- Multiple drains have persistent problems
Professionals can use camera inspections to find hidden breeding sites. They have tools to clean deep inside pipes where you can’t reach. They can also fix plumbing issues that create breeding conditions.
Conclusion
Drain flies are a clear indicator of organic buildup in your plumbing. The solution is simple: eliminate the source of the food. By using mechanical tools to scrape, followed by biological gels to digest the biofilm, you can permanently answer how do I get rid of drain flies and maintain a healthy, pest-free plumbing system. This systematic approach is the only way to avoid the frustration of seeing them return.
Need help with stubborn drain problems or want professional drain cleaning? Derks Plumbing offers expert Drain Cleaning in Eagle Rock and surrounding areas. Our team can identify hidden breeding sites and provide lasting solutions for your plumbing needs.
FAQs
How long does it take to get rid of drain flies?
Most infestations clear up in 7-10 days with daily drain cleaning. You might see adults for a few days after treating drains because eggs were already laid. Keep treating drains until you see no new flies for three days straight.
Can drain flies come from the toilet?
Yes, drain flies can breed in toilet drains, especially if the toilet isn’t used often. The slime ring under the rim provides a breeding spot. Clean toilet drains the same way you clean sink drains.
Do drain flies die in winter?
Indoor drain flies don’t die in winter because your home stays warm. They breed year-round in heated buildings. Outdoor drain flies become inactive in cold weather but come back when it warms up.
Can drain flies make you sick?
Drain flies don’t bite or sting. They’re not known to spread diseases to humans. But they’re unsanitary because they breed in dirty drains. Large infestations can trigger allergies in sensitive people.
Why do I only see drain flies at night?
Drain flies are most active in evening hours. They rest during the day on walls near their breeding sites. You’ll notice them more at night when they fly around looking for mates and new places to lay eggs.
