How to Get Rid of Drain Flies? 6 Easy Steps Guide for Homeowners

Drain flies, also known as sewer flies, filter flies, or moth flies, are one of those small household nuisances that can quickly turn into a bigger problem if not handled properly. They are fuzzy, tiny insects that love to live and breed in moist, organic buildup inside sink drains, bathroom pipes, and even around septic tanks. While they do not bite or transmit disease, they are still unwelcome guests in any home or business.

At Drain Pro Plumbing, we help Washington homeowners with professional drain cleaning, plumbing repairs, and pest prevention. In this detailed guide, we will walk you through everything you need to know about how to get rid of drain flies permanently.

What Are Drain Flies?

Understanding what you are up against is the first step to success.

• Size and appearance: Drain flies are small, usually 1/16 to 1/4 inch in length, with hairy bodies and wings shaped like tiny leaves. Their fuzzy look makes them resemble small moths.

• Behavior: They are weak fliers and often move in short, hopping patterns rather than straight lines. You may notice them resting near a sink drain or bathroom wall.

• Preferred environment: They thrive in places where water sits for long periods and organic material builds up, such as sink drains, floor drains, or septic tank areas.

Unlike fruit flies which are attracted to sugary food, drain flies rely on the slimy film in your plumbing for survival.

Why Do Drain Flies Appear in Homes?

The presence of drain flies is a signal that you have standing water or organic buildup somewhere in your plumbing system. Some of the most common reasons include:

1. Clogged sink drains: With moist, slimy buildup.

2. Slow bathroom drains: With soap scum, hair, and toothpaste residue.

3. Septic tank issues: Where lids are leaking or poorly sealed.

4. Rarely used pipes: That allow water to sit.

5. Moisture leaks: From faucets or loose connections under sinks.

Life Cycle of a Drain Fly

Knowing their life cycle helps explain why simple swatting does not work.

• Eggs: Females lay 30 to 100 eggs at a time in moist, organic matter inside drains.

• Larvae: Within 48 hours, larvae emerge and feed on the organic slime.

• Pupae: After about 9 to 15 days, they pupate in the slime.

• Adults: Adult drain flies live for about 20 days but reproduce quickly, making infestations persistent.

Because they breed in hidden biofilm, surface cleaning alone is rarely enough. You must target the source inside the pipe.

How to Get Rid of Drain Flies: Step by Step Process

Step 1: Confirm You Have Drain Flies

Before starting drain cleaning, be sure you are dealing with drain flies and not fruit flies or gnats.

The tape test:

1. Place a piece of clear tape sticky side down over the suspected drain, leaving a small gap for air.

2. Check after 24 hours. If small flies are stuck to the tape, you have confirmed the breeding site.

Check multiple drains in your home including bathroom sinks, kitchen sinks, shower drains, and basement floor drains.

Step 2: Locate the Breeding Site

Drain flies rarely stray far from their breeding source. Check these locations carefully:

• Kitchen sink drains: With food residue or grease buildup.

• Bathroom sinks and showers: With toothpaste, soap, and hair buildup.

• Floor drains: In basements, garages, and laundry rooms.

• Septic tanks or sump pumps: With cracks or leaks around lids.

Step 3: Clean the Drains Thoroughly

Once you have found the source, it is time for a deep clean.

Scrub the Drain

Use a stiff drain brush designed for sink drains. Push it down into the pipe and scrub away slime and buildup. This removes eggs and larvae clinging to the drain walls.

Flush with Boiling Water

Boiling water is an inexpensive and effective method. Carefully pour 2 to 3 kettles of boiling water down the sink drain, repeating daily for several days. This loosens slime and kills larvae.

Use Enzyme Drain Cleaners

Bio-enzyme or bacterial drain cleaners are eco-friendly options that break down organic matter naturally. Unlike chemical drain cleaners, they target the breeding source without harming pipes or septic tanks.

Baking Soda and Vinegar Method

For a natural DIY solution:

1. Pour ½ cup of baking soda into the sink drain.

2. Follow with ½ cup of vinegar.

3. Let the mixture fizz for 15 minutes.

4. Flush with hot water.

This not only kills larvae but also deodorizes your drain.

Step 4: Maintain Clean Drains

Eliminating an infestation is only half the battle. Preventing future issues is just as important.

• Regular cleaning: Make drain cleaning part of your monthly home maintenance routine.

• Dry sinks at night: Wipe sinks dry and close the drain to cut off moisture.

• Install drain covers: For rarely used drains, install maintenance solutions like covers or stoppers.

• Fix leaks promptly: Even small drips under a sink can keep surfaces damp and inviting for flies.

• Flush unused drains: Pour water into guest bathroom or utility sink drains weekly to prevent stagnation.

Homeowners who follow these steps rarely wonder about how to get rid of drain flies a second time.

Step 5: Use Natural Repellents and Traps

While cleaning eliminates the larvae, adult flies may still be present. Here are safe, natural ways to capture them:

• Apple cider vinegar trap: Fill a small bowl with ¼ cup apple cider vinegar and a drop of dish soap. Place it near the drain. Flies will be attracted and trapped.

• Essential oil spray: Mix 10 drops of peppermint or eucalyptus oil with water in a spray bottle. Spray around sink drains and bathroom areas.

• DIY light trap: At night, place a bowl of soapy water under a lamp near the sink drain. Flies drawn to the light will drown in the bowl.

If you have researched how to get rid of drain flies, you have likely seen all three of these natural remedies recommended.

Step 6: When to Call a Professional

If you have tried multiple cleaning methods and still have an infestation, it may be time to bring in a professional plumber. At Drain Pro Plumbing, we offer:

• Professional drain cleaning services: Using specialized equipment that clears even the toughest buildup.

• Septic tank inspection and maintenance: For homes with septic systems.

• Full plumbing repair services: For leaks, pipe damage, and long-term prevention.

Sometimes the problem is deeper in the plumbing system than a homeowner can reach. That is why professionals are often the final answer to how to get rid of drain flies for good.

Commercial Buildings and Drain Flies

Drain flies are not just a household issue. Businesses can suffer too:

• Restaurants and cafes: With food residue in sink drains and grease traps.

• Hotels: Where bathroom drains in multiple rooms can harbor pests.

• Warehouses and factories: Where floor drains and tank water storage areas may become breeding sites.

In these cases, ongoing install maintenance programs for drains and plumbing are recommended to prevent infestations that could harm a business reputation.

Septic Tanks and Drain Flies

Homeowners with septic tanks must pay extra attention. A cracked or leaking septic tank lid can create an outdoor breeding site. If you notice flies outdoors near your septic tank or drain field, call for professional septic tank inspection immediately.

Bathroom and Sink Drain Hotspots

Bathrooms are one of the most common places drain flies appear. Soap scum, hair, and moisture make a sink drain or shower drain ideal for breeding. Preventive bathroom care includes:

• Cleaning drains weekly: With baking soda and vinegar.

• Using drain covers: To catch hair.

• Running hot water: After brushing teeth or washing hands.

If you have ever searched how to get rid of drain flies in the bathroom, these are the first steps to take.

Can Tankless Water Systems Help?

While not a direct fix, homes with tankless water heaters sometimes see fewer drain fly issues compared to homes with older tank water systems. This is because tankless water heaters provide hot water on demand, encouraging homeowners to flush drains with hot water more often. Regular hot water flow helps keep pipes cleaner.

FAQs About Drain Flies

1. How to get rid of drain flies quickly?

• The fastest method is scrubbing your sink drain with a drain brush, flushing with boiling water, and applying enzyme drain cleaner. This attacks both larvae and organic slime.

2. Do drain flies mean my home is dirty?

• Not necessarily. Even clean homes can have hidden buildup inside drains. The key is regular drain cleaning and maintenance.

3. Will bleach kill drain flies?

• Bleach may kill some larvae but often does not remove the organic slime where they live. Enzyme cleaners or baking soda and vinegar are more effective.

4. Can drain flies live in toilet tanks?

• It is rare, but if water sits unused, they may appear. Flushing toilets daily and keeping them clean prevents this.

5. How do I stop drain flies from coming back?

• Prevention is key. Routine drain cleaning, fixing leaks, drying sinks, and covering unused drains will keep infestations away.

6. Should I call a plumber for drain flies?

• Yes, if home remedies fail or if flies keep returning. Professionals have the tools to clean deep inside drains and even inspect septic tanks if needed.

Professional Drain Cleaning Services in Western Washington

Learning how to get rid of drain flies is all about consistency. Identify the breeding site, clean it thoroughly, maintain a dry environment, and use traps for lingering adults. If infestations continue, professional drain cleaning services are your best solution.

For homeowners and businesses in Western Washington, Drain Pro Plumbing is here to provide expert help. From septic tank inspections to bathroom sink drain cleaning, our services are designed to keep your plumbing running smoothly and your home pest free.

At Drain Pro Plumbing & Septic, we provide comprehensive drain cleaning, septic tank maintenance, and plumbing repair. Our services ensure your home stays free from pests like drain flies while keeping your plumbing system healthy. Whether it is a clogged sink drain, a septic issue, or a leak in your bathroom, our expert team is here to help. Call us at (253) 352-3927.