Drain flies are one of those problems that start small but quickly become frustrating. You might see a few hovering near your sink one day, and within a week, it feels like they’ve taken over your bathroom or kitchen. The good news is that they can be dealt with effectively. Here’s how to get rid of drain flies for good, based on real plumbing expertise.
Drain flies thrive in places with standing water and organic buildup. They breed in the gunk lining your pipes, which provides both food and a safe place to lay eggs. Kitchens, bathrooms, and utility rooms are common hotspots because sinks, showers, and floor drains are perfect breeding grounds if they’re not maintained properly.
If you notice drain flies, it’s a clear sign that there’s a buildup in your drains. While they don’t bite or spread disease, they indicate that your drainage system needs attention.
The first step in learning how to get rid of drain flies is figuring out where they’re coming from. Cover your drains overnight with tape, sticky side down. If flies are stuck to the tape in the morning, you’ve found the breeding site. Do this with every suspect drain until you know exactly where the problem is.
It’s important to check less obvious places as well, such as unused floor drains, sump pump pits, or even the overflow holes in sinks. Drain flies don’t travel far from their breeding site, so the source is always close by.
Pouring bleach or boiling water down the drain won’t solve the issue. These quick fixes kill surface flies but don’t remove the breeding material. To get rid of drain flies permanently, you need to clean the pipe walls.
Start with a stiff drain brush to scrub the inside of the pipe. Follow with a drain-safe cleaner designed to break down organic buildup, such as enzyme-based solutions. These cleaners work better than harsh chemicals because they eat away at the debris where flies breed instead of just pushing it further down.
At FS Group, we often find that a CCTV drain survey is the fastest way to confirm where buildup is happening. It gives a clear picture inside the pipe and ensures cleaning is targeted at the real source.
After cleaning, flush the drain with plenty of hot water to wash away loosened debris. Then, keep the area dry whenever possible. Flies need damp conditions to survive, so reducing moisture is key. Wipe down sinks after use, check for small leaks under taps or fittings, and run water regularly in drains you don’t often use.
To stop them from returning, use an enzyme drain cleaner once a week. It’s safe, effective, and prevents organic buildup from forming again.
Sometimes the infestation keeps coming back even after you’ve cleaned the drains. This usually means the breeding ground is deeper in the system, or there’s a structural issue like cracked pipes collecting stagnant water. In these cases, professional help is the only real solution.
Plumbers can carry out deep cleaning using mechanical equipment or perform a full CCTV inspection to spot hidden buildup, blockages, or structural defects. At FS Group, we regularly deal with these situations for large maintenance companies and homeowners alike, clearing infestations and fixing the underlying cause in one visit.
One of the biggest mistakes people make when trying to figure out how to get rid of drain flies is relying on bleach.
Bleach kills some larvae on the surface but doesn’t penetrate the thick biofilm in your pipes. Worse, it can damage your plumbing if used repeatedly. Professional-grade solutions are designed for the problem and actually clear it without harming your system.
That’s why our team always uses targeted drain cleaning methods rather than chemical shortcuts. It’s safer for your home and more effective in the long run.
If you’ve found the source and cleaned it properly, you should see results within a week. Adult flies only live around 20 days, so once breeding stops, the problem clears quickly. If you’re still seeing flies after two weeks, chances are you’ve missed a breeding site. That’s when calling a professional becomes the fastest option.
With our emergency response team available for drainage issues, FS Group can usually resolve infestations within a single visit, ensuring the system is clean and fly-free.
The best long-term solution is prevention. Keep your drains clean and clear, don’t ignore slow drainage, and avoid letting sinks or showers sit damp for long periods. Regular maintenance is far easier and cheaper than dealing with a full-blown infestation.
For businesses and landlords, scheduling regular drain inspections is one of the simplest ways to avoid repeated drain fly problems. At FS Group, we provide both planned maintenance and emergency callouts, helping large maintenance companies stay ahead of issues before they turn into infestations.
Knowing how to get rid of drain flies comes down to removing the breeding source, not just spraying or pouring chemicals. With the right cleaning, maintenance, and sometimes professional support, you can clear them for good.
If you’re struggling with drain flies or want peace of mind that your drainage system is in top condition, our team is ready to help. Give us a call today!
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