The Facilities Manager’s Guide to How to Get Rid of Drain Flies

Picture this: you’re the manager of a bar. Lately, gnats seem to be spawning all over the establishment—on the walls, the floors, the drains, the glasses. Every day, you hear worker and customer complaints, and you’re growing increasingly concerned about health inspections. You’ve tried insecticides to no avail; how can you eliminate these pests and get your facility back on track?

At State Chemical, we manufacture and distribute chemical and biological solutions for various applications, including drain fly control. We understand that when presented with pest problems, you want the quickest, most pain-free solution.

To help you solve your drain fly problem, we will explain what drain flies are, what an infestation may look like, what negative consequences you may face, and how to eliminate drain flies. After reading, you’ll know how to keep your facility clean and pest-free.

What are Drain Flies?

In order to understand how to eliminate drain flies, you first must understand what a drain fly is.

To the blind eye, drain flies look like gnats or fruit flies. However, if you look more closely, you’ll see that drain flies are more like a cross between a housefly and a moth. They’re fuzzy with bigger wings, and they never venture far from your drains.

Drain flies thrive in drains because of the fats, oils, and greases (FOGs) that go down every drain with normal usage. For example, in a facility like a food processing plant, food scraps and FOGs constantly enter the drain, building up and clinging to the sides of the pipes over time.

Enter drain flies. These pests use FOG buildup as a food source, breeding ground, and habitat all in one. As long as there are FOGs in the drain, drain flies will continue multiplying and invading the facility.

Meanwhile, fruit flies will feed on fruit, and gnats are more attracted to the organic matter in soil. If the flies in your facility seem to be attracted to areas other than drains, you are not experiencing a drain fly problem.

What Do Drain Fly Problems Look Like in Commercial Facilities?

When you have a drain fly problem in your facility, the issue probably isn’t immediately obvious to start. At first, you might only notice one or two crawling around. But once they’ve been given the chance, drain flies will reproduce, and their presence will be more apparent.

Once this happens, you’ll see drain flies on surfaces around your drains. Drain flies actually aren’t great at flying, so you’ll mostly notice them lounging around. If you look down into your drains, you might even be able to see the larvae wriggling in the water.

Depending on your specific drain, this can look different, but there are many common problem areas.

Drain Flies in Bar Drains

In a bar, drain flies are drawn to the sugars in beer and other spirits that go down the drain. Because of this, they’ll quickly reproduce in drains containing this type of buildup (i.e., bar drains).

This means that in a bar, you’ll likely see drain flies gathered around sinks, glassware, counters, and any other surface close to the drain. For obvious reasons, this creates sanitation concerns.

Drain Flies in Soda Fountain Drains

Drain flies are often drawn to soda fountain drains because of the sugary sludge buildup they’ll encounter there. This buildup acts as a food source and habitat for them: the perfect place to lay their eggs in and subsist on.

As a result, these pests don’t often stray too far from the soda fountain drain, making it easy to trace their source.

Drain Flies in Floor Drains

When the problem is your floor drain, drain flies will typically hang around the floor, walls, and any nearby equipment. You may also be able to look down these drains and notice visible larvae.

Drain flies survive on organic matter from substances like spilled grease in floor drains.

For example, if you work in a fast-food restaurant, it’s likely that cooking oil will splash onto the floor, food will fall off counters, and drinks will get spilled—mistakes happen, after all. But when remnants of these organics end up on the floor, they get washed into the floor drains when you mop—and then the drain flies have both a food source and a habitat in these drains.

Drain Flies in Mop Basins

Just as organics find their way into floor drains, mops easily pick up residue that can cause buildup in mop basins.

Again, picture the fast-food restaurant, but instead of the debris being pushed into floor drains by the mop, the mop head gathers the debris in its fibers and deposits it in the mop bucket. Once the mop bucket is dumped down the mop basin and the mop is placed there to dry, all the organics collected wash down the basin, and there is now a food source and potential habitat for drain flies.

Drain Flies in Sink Drains

Of course, the classic setting for a drain fly is in an ordinary sink. Drain flies will end up in everyday sinks for the same reason they’ll end up in any other drain: because there are FOGs there for them to consume and lay their eggs in.

These FOGs can come from more obvious sources, like food scraps drained during dishwashing, or from less obvious sources, like the body oil from washing your hands. Whatever the case, once FOGs build up in your drains, these drains become an ideal location for drain flies to put down roots.

How Drain Flies Impact Commercial Facilities

Obviously, drain flies are gross—no one feels clean or at ease when visible insects are hanging around—but what adverse effects might they have on your facility?

The most glaring problem that drain flies may lead to is a health code violation. Drain flies are not known to cause disease in humans, but they are known to trigger allergic and asthmatic reactions because of the dust and fragments from their bodies.

Additionally, they can carry bacteria from your drain into other areas of your facility. They live in filth, so the filth they gather is easy for them to track around, making them a red flag for health departments.

However, aside from just the health department repercussions, these pests can cause harm to your staff and customers. When there’s a chance for allergic and asthmatic reactions and drain flies carrying pathogens, the way to keep users of your facility safe is by treating the issue.

Plus, if customers see drain flies in your facility, it will be a big turnoff, and they’ll be less likely to visit your facility again. Similarly, with an annoying and nasty pest invasion, employees probably won’t view your workplace as a safe and healthy environment.

How to Get Rid of Drain Flies in Commercial Facilities

Drain flies aren’t something you want to welcome into your facility, so how should you get rid of them? The only way to deter drain flies from your facility is to eliminate their habitat. You can swat at individual flies to deal with isolated incidents, but to get to the root of the issue, habitat elimination is your only option.

Depending on the severity of your issue, you can do this in a few ways:

Boiling Water

For minor infestations (e.g., you’ve only noticed a few drain flies), pouring boiling water down the drain may be an effective solution for you. This works by temporarily melting the FOG buildup that the drain flies live in and moving it down the drain line.

However, if your issue is moderate or severe, this is not the solution for you. More significant drain fly problems indicate more buildup, so if their habitats stretch further down the drain line, boiling water won’t help. It will only treat the top of the drain, and the drain flies will have no trouble rebuilding from the bottom.

Baking Soda and Vinegar

Another solution to more minor infestations is to pour one cup of vinegar and half a cup of baking soda down your drain. This will clear out the buildup from the top of your drain, eliminating drain fly habitats.

However, this still does not get to the root of bigger problems. As the solution carries down your pipes, it will become diluted and will not effectively clean buildup further down the line. Again, this is not ideal for bigger issues or as a long-term solution.

Metal Scrub Brush

A metal scrub brush can be an effective solution for moderate drain fly problems. As far down as your metal scrub brush will reach, you can scrub FOG buildup off the inside walls of your pipes, taking out drain fly habitats firsthand.

If your issue is severe, this solution won’t help because your buildup likely spans further down the pipes than your brush can reach. But for mild-to-standard buildup, this method ensures the thorough removal of drain fly habitats.

Commercial Drain Cleaner

For moderate-to-severe issues, you should use a commercial drain cleaner specifically designed to eliminate drain fly habitats. Drain cleaners work by clearing FOG buildup through your pipes, either through emulsification or bacterial digestion. This removes the drain flies’ habitat, food source, and breeding grounds all in one, and it works all the way down the line from where it enters.

This action is not usually necessary with minor drain fly problems. However, commercial drain cleaners get to the root of the problem and prevent future buildup that could attract drain flies later. In this way, it can also be used as preventative maintenance even after you get rid of drain flies in your facility.

Learn How State Chemical Can Help Your Facility Eliminate Drain Flies

When your facility is faced with a drain fly infestation, it’s stressful, gross, and overall unpleasant. Now that you know which solution you need to get rid of drain flies, watch the video below to learn how State Chemical can help your facility eliminate this problem with NO Contest™.