Drain Fly Dilemma: Hire An Exterminator or Plumber?

Treating drain fly infestations using homemade solutions can be a long and time consuming process. The reality of most infestations is that drain pipes need to be scrubbed in order to remove scum and food sources.

Drain flies, or Psychodidae, are poor fliers that tend to breed in drains. Females lay eggs in the scummy buildup in drainpipes or standing water.

Removing Drain Flies

Eliminating adult drain flies is easy enough. They are slow fliers. But if you don’t remove their breeding ground, it will only be a matter of days before they reappear. DIY treatment programs must include scrubbing pipes and a biocide to help remove organic buildup on which the fly larva feed.

Sometimes, no matter how much effort you put in, those little flies will keep coming back. This can be an indicator of a larger issue, such as with your sewer line.

Why Choose an Exterminator?

If you already tried to treat drain flies on your own to no avail, you may want to consider hiring a professional exterminator. The reason why an exterminator is better equipped to handle drain flies is their background in entomology. Exterminators understand drain flies, their life cycle, and how to best get rid of them.

Plumbers may be able to open the pipes and clean out blockages after the issue is diagnosed. However, exterminators can also help with this process by using organic enzyme drain cleaners or gels. These work by ‘eating’ the organic material buildup in pipes and drains where flies are living. In some cases, you may have to work with both types of professionals to get the job done.

When to Hire a Plumber

Unfortunately, drain flies can be a chronic issue, even after you clean pipes and other suspected sources. In many cases, the most important factor is to have a solid program in place. Even after you check other possible indoor breeding areas, such as sump pits, potted plants and drip pans, you may still see the annoying pests.

basement floor being opened to fix sewer line
One a recent job, our plumbers had to break up the floor to fix sewer leakage into a sump pit.

If nothing you do seems to work, you may be dealing with a broken sewer pipe under your home’s slab. In this scenario, a plumber will be needed to break open the concrete flooring, remove the contaminated soil, and repair the pipe.

Verifying a Leak Using Fluorescent Plumbing Dye

If you suspect a break in your sewer line, there are ways you can test for leaks prior to calling a plumber. Pour fluorescent dye into your toilet and flush. If you see the dye appear in your sump pit, coming up from floor drains or cracks, you have an issue.

Video showing fluorescent dye in sump pit water with black light on and off.

Common Questions & Answers

Can an exterminator get rid of drain flies?

Yes, they can get rid of them in basic situations. However, they may not be equipped to help you if the problem lies with a broken sewer line or buildup deep inside your main lines.

Can a plumber get rid of drain flies?

Yes! A plumber is likely better equipped to deal with issues related to difficult infestations. This includes checking your main line if all else fails. Plumbers can also use pressure jetting and manual cleaning to remove buildup from pipes, traps and drains.

I cannot find where flies are coming from, what can I do?

Drain flies tend to remain near the area where they breed. Check your drains using the tape-over method for 24 hours. You can also call in a plumber to check pipes and look for common and uncommon areas of infestation.

Plumber or exterminator: who charges more for removing drain flies?

This is a question that will require you to call around and get some quotes. If the flies just will not disappear, a plumber is your best bet, as they can check and snake your lines. The average cost for a plumbing job ranges from $45-300+. Exterminators average price is $125-200.

Treating Infestations Yourself

Yes, this is an option too!

Learn how to identify flies and then determine where they are coming from. Your issue might be easily fixed with some manual labor and a good drain gel. You can also do the detective work yourself, instead of relying on a plumber or exterminator, who will otherwise wrap this into their price.

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