How to Get Rid of Drain Flies

Drain flies (also called sink flies or moth flies) are tiny gray or black insects that live and breed in the slimy gunk inside drains. You’ll often see them around sinks, showers, or floor drains. They are about 1/8 inch long, with fuzzy bodies and wings that make them look like small moths. These flies live and breed in the slimy organic matter that builds up inside drain pipes. They feed on decaying materials, soap scum, and moisture. While drain flies don’t bite or spread serious diseases, they can quickly multiply and become annoying. Getting rid of them requires cleaning drains thoroughly and removing the buildup where they lay eggs.

🚿 Step-by-Step: How to Get Rid of Them

1. Find the Source

• Look in sinks, tubs, or floor drains.

• Cover each drain with plastic wrap overnight.→ If flies stick to the underside, that’s the problem drain.

2. Clean the Drain

• Pour boiling water down the drain (2–3 times a day).

• Use a drain brush or old toothbrush to scrub the inside walls.

• Mix ½ cup baking soda + ½ cup salt + 1 cup vinegar, pour into drain, and let sit overnight. In the morning, flush with hot water.

3. Use Enzyme Cleaner

• Use a biological drain cleaner (enzyme-based, not harsh chemicals).It breaks down the organic slime where flies breed.

4. Trap Remaining Flies

• Put out a vinegar trap:Mix apple cider vinegar + a few drops of dish soap in a small bowl near the drain.The flies will get trapped.

5. Keep Drains Dry & Clean

• Run hot water daily to keep drains clear.

• Clean strainers and stoppers weekly.

• Don’t let standing water sit in sinks or tubs.

How to Tell Drain Flies and Fruit Flies Apart

Drain flies are found around sinks, showers or floor drains. Whereas, fruit flies are found near fruits, garbage bins, or open food.

Where Do Drain Flies Come From?

To eliminate drain flies, it's essential to identify their source. These flies usually stay close to their breeding area, so if you notice them, inspect the nearby drains. Occasionally, their breeding ground might be outside your home, such as compost piles, animal waste, storm drains, garbage collection sites, birdbaths, or barns.

🧰 How to Inspect Drains for Drain Flies

If you see tiny flies near your sinks or tubs, the first step is finding where they’re breeding. Here are two easy methods to check your drains:

1. Duct Tape Test

Cover the top of the suspected drain with clear duct tape, sticky side down, and leave it overnight.If you see small flies stuck to the tape in the morning, that drain is the source of the problem. Once confirmed, you can focus on cleaning that particular drain to remove their breeding area.

2. Check for Larvae

Sometimes, adult flies are hard to spot. If the tape test doesn’t work, remove the drain cover and look inside using a flashlight. Drain fly larvae look like tiny, worm-like tubes.Use a pipe brush or a drain snake to scrub away any slime, hair, or organic matter inside the pipe — that’s where the larvae usually live and feed.

🧼 How to Get Rid of Drain Flies Naturally

Once you find the source, you can easily get rid of drain flies using natural methods instead of harsh chemicals:

1. Vinegar and Baking Soda

Pour ½ cup of baking soda followed by 1 cup of vinegar down the drain.Cover the drain and let it sit for 30 minutes. This mixture breaks down grime and kills larvae.Finish by flushing the drain with boiling water.

2. Boiling Water Flush

Simply pour boiling water down the drain once or twice a day for a few days. This helps remove the sticky biofilm that flies feed on.

3. Apple Cider Vinegar Trap

Mix apple cider vinegar and a few drops of dish soap in a shallow bowl. Place it near the drain overnight.Flies are attracted to the vinegar but get trapped in the soapy water.

4. Enzyme-Based Drain Cleaner

Use a microbial or enzyme cleaner to dissolve organic buildup inside pipes. These cleaners are eco-friendly and safe for plumbing while eliminating both larvae and their food source.

⚠️ When to Call a Professional

If the infestation keeps coming back, it might mean there’s buildup deeper inside the pipes or in hidden areas.A pest control or plumbing professional can use special drain treatments or safe chemical cleaners like peracetic acid to clear the problem completely.

Avoid using strong chemicals like bleach on your own — it can harm pipes, septic systems, and may not fully remove larvae or eggs.

🧯 How to Prevent Drain Flies from Coming Back

Once you’ve gotten rid of drain flies, it’s important to keep them from returning. The key is to remove moisture and organic buildup that attract them.

• Eliminate Standing Water: Check for any areas where water collects — such as leaky pipes, dripping faucets, clogged gutters, or water sitting under sinks. Even damp flowerpots can become breeding spots.

• Keep Drains Clean: Flush drains with hot water regularly and use a mild enzyme cleaner once a week to stop slime from building up.

• Maintain Good Hygiene: Wipe kitchen counters, clean up food crumbs, and avoid leaving dirty dishes or wet sponges overnight.

• Schedule Routine Plumbing Checks: Regularly inspect your plumbing for slow drains or leaks. Fixing them early prevents the moist conditions drain flies love.

By keeping your home dry, clean, and well-maintained, you’ll stop drain flies before they have a chance to come back.

🪰 Frequently Asked Questions About Drain Flies

1. What causes drain flies to appear?

Drain flies are attracted to stagnant water and organic buildup. They usually breed in sink drains, shower pipes, floor drains, or any place with moisture and decaying matter.

2. Are drain flies harmful?

No, drain flies don’t bite or spread serious diseases. However, they can carry bacteria from dirty drains onto surfaces, which may cause mild hygiene issues.

3. How long do drain flies live?

An adult drain fly lives about two weeks, but it can lay up to 100 eggs at a time. That’s why infestations can grow quickly if drains aren’t cleaned regularly.

4. Can drain flies come from toilets?

Yes. If the toilet isn’t used often or has a broken seal, drain flies can breed in the water and organic residue inside the pipes.

5. Do drain flies fly slowly or fast?

Drain flies are slow, weak fliers. They usually hover near walls, sinks, and drains instead of flying long distances.

6. Do drain flies come back after cleaning?

They might, if the root cause (moisture and buildup) isn’t fixed. Regular cleaning and maintenance are key to keeping them away permanently.

7. What smells repel drain flies?

Strong scents like lemon, eucalyptus, peppermint, or vinegar can repel them. Using natural sprays or cleaning solutions with these fragrances can help.

8. Can drain flies lay eggs in clean drains?

No. Drain flies need a layer of organic slime to survive. Clean drains without buildup are not suitable for breeding.

9. How do I know if I have drain flies or gnats?

Drain flies have fuzzy, moth-like wings and rest near drains, while gnats are smaller, sleeker, and faster and tend to hover around plants or fruits.

10. Should I call a pest control professional for drain flies?

If natural remedies and cleaning don’t work within a week or two, it’s best to contact a pest control expert. They can inspect hidden breeding spots and use safe treatments to eliminate the infestation.