How to Get Rid of Drain Flies (Causes, DIY Fixes & Permanent Solutions)

Drain flies around a bathroom floor drain in a Sydney home

Drain flies, also known as moth flies or sewer flies, are a common household nuisance, especially in bathrooms, kitchens, and laundry areas. While they’re not harmful, they can multiply quickly and usually indicate a deeper issue inside your drains.

If you’re wondering how to get rid of drain flies for good, this guide explains what causes them, which DIY methods actually work, and when professional plumbing is needed to stop them permanently.

What Are Drain Flies and Why Do They Appear?

Drain flies are small, fuzzy insects that thrive in damp environments. Unlike fruit flies, they don’t come from food left out on benches; they breed in organic buildup inside drains, floor wastes, and pipes.

They’re often a sign of:

Killing the flies alone won’t solve the problem unless the source is removed.

Common Causes of Drain Flies in Australian Homes

Drain flies are usually linked to one or more of the following issues:

In older Australian suburbs, clay pipes and mature trees can make drain fly issues more frequent.

How to Get Rid of Drain Flies (DIY Methods That Work)

If the infestation is minor, you may be able to reduce drain flies with the following DIY steps. These work best when the drain is slow but not fully blocked.

1. Clean the Drain Thoroughly

Use a stiff drain brush to scrub the inside of the drain opening and remove visible sludge. This is the most important step — surface cleaning alone is not enough.

2. Boiling Water Flush

Slowly pour boiling water down the drain in stages to help dissolve grease and organic residue. This can reduce breeding material.

3. Baking Soda and Vinegar Treatment

Pour half a cup of baking soda into the drain, followed by half a cup of vinegar. Allow it to fizz for 15–20 minutes, then flush with hot water.

4. Use a Plunger

For soft blockages, plunging can help dislodge buildup further down the pipe.

⚠️ Avoid chemical drain cleaners. They can damage pipes and rarely remove the organic sludge that drain flies feed on.

Room-Specific Drain Fly Tips

Bathroom & Shower Drains

Kitchen Drains

Toilets & Floor Wastes

Natural Remedies for Drain Flies

Natural methods can help reduce fly activity, but they won’t fix deeper drainage problems.

These methods are best used alongside proper drain cleaning.

When DIY Methods Aren’t Enough

If drain flies keep returning, there’s usually an underlying plumbing issue.

You should contact a licensed plumber if:

Professional plumbers use CCTV drain inspections and high-pressure water jetting to remove organic buildup completely, something DIY methods can’t achieve.

Organic sludge buildup inside a household drain pipe

How to Get Rid of Drain Flies Permanently

Permanent removal requires eliminating the breeding source inside your pipes.

Long-term solutions may include:

Without fixing the underlying cause, drain flies will keep returning.

Preventing Drain Flies from Coming Back

Once the problem is resolved, prevention is key.

Routine maintenance is far cheaper than emergency plumbing repairs. Maintaining clean drains and household hygiene is also recommended by NSW Health to reduce sanitation and pest risks.

Frequently Asked Questions

What are the early signs of drain flies?

Small flies near drains, slow drainage, gurgling noises, and unpleasant smells are common early indicators.

Are drain flies dangerous?

No, but they indicate unsanitary conditions inside your drainage system.

Will vinegar alone remove drain flies?

Vinegar can reduce adult flies, but it won’t remove the organic buildup causing the problem.

Can drain flies mean a blocked drain?

Yes. Drain flies often indicate partial blockages or stagnant water inside pipes.

Should I call a plumber for drain flies?

If DIY methods don’t work or the problem keeps returning, professional plumbing is recommended.

Need Help Getting Rid of Drain Flies?

If drain flies keep coming back, it’s often a sign of deeper pipe or drainage issues. Civic Plumbing provides professional drain cleaning, CCTV inspections, blocked drain services, and preventative maintenance across Sydney.

Call 0410 790 630 to book an inspection and stop drain flies at the source permanently.

Civic Plumbing
Civic Plumbing
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Renae Pettit
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Chris has undertaken various large remedial works of the underground sewer pipes at our place as well as work on our recent renovation. Chris is always professional, communicative and finds solutions for challenging plumbing situations. We thoroughly recommend Chris and his team for your plumbing needs.

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Thanks Renae and always a pleasure
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Kate Lawrie
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Chris was super helpful, professional and responsive. We would highly recommend him & won’t hesitate in calling Chris for any future plumbing needs.

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Thanks Kate!
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Duncan Stewart
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Found CIVIC online - they responded quickly. Chris was quick on the phone and quick to get his team out. Better yet it was actually a local company not some dirty grifter from the western suburbs advertising in our area to try and get eastern suburbs money. I gave him about 10 things on the list and we agreed a price. The specialist was there early, did each task to a high standard and was very polite and courteous all the way through the work. Cleaned up after himself, checked everything with me and then asked if he could go. Manners - 100 out of 10. Top knotch. The price of the service was reasonable And the professionalism and courtesy was exceptional. I highly recommend them and we will use them again.

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Thanks for your great review Duncan. You were a pleasure to work with and will pass on the great feedback for Milo also.
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Joel Reddy
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Civic plumbing saved my hide! The bloody pipe broke in my apartment and I didnt know what to do. Chris saved the day!!
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KARINA CHAN
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Quick same day service and reasonable pricing to fix my kitchen tap. Thank you Chris ☺️

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Thanks for the review.
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M. G Squared
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Chris from Civic Plumbing provided excellent service. He diagnosed and corrected our problem quickly and efficiently, with perfect timing and no delays. Really impressed with the professionalism and responsiveness—awesome experience overall!

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Thanks for the feed back!
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Connor fheyman
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Had a plumbing issue come up at the worst possible time and gave Civic Plumbing a call not really expecting anyone to pick up. They actually answered after hours and talked us through the whole thing with honest advice. Really refreshing dealing with someone who's not trying to upsell you on stuff you don't need. Would definitely recommend them to anyone around Sydney. 👍
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Gabriel Simon
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Chris and his team at Civic Plumbing epitomise the concept of professional business. Civic Plumbing are reliable, honest and offer high quality service/work. I would recommend Civic Plumbing for all types of work (commercial or residential). 5/5!

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Thanks Gabriel