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How to Get Rid of RV Bathroom Flies

How to Get Rid of RV Bathroom Flies

You arrive at your camper ready to clean it up and get it ready for the camping season. Only instead of being greeted by a few spider webs, you find tiny flies crawling and flying all around the drain in your bathroom sink.


We look at why this may have happened, what you can do to get rid of these pests, and how to prevent such a problem in the future. 

Let’s dig in!

Why Are There Flies or Gnats in Your RV Bathroom?

Insect larvae are usually hidden. You don’t see them until they’re not larvae anymore. Typically, insects will lay their eggs near waste, usually in bathrooms near sewer waste and kitchens near food waste.

This is why you’ll find gnats, flies, and other insects around the toilet or kitchen sink, especially in an RV with black and gray tanks underneath.

Set of insects fly on white

Can Sewer Flies Affect Your Health?

Don’t panic if you find flies or gnats in your bathroom or anywhere in your RV. A few of them aren’t going to do much damage. However, if you leave them alone, these insects will reproduce. Then you might have a much bigger problem.

The flies and gnats themselves don’t transmit diseases to people, but they can carry bacteria from the waste and spread it around your RV.

How Do You Get Rid of RV Bathroom Flies?

First, try to be proactive rather than reactive. Before ever seeing your first fly or gnat, keep all surfaces sanitized. Keep your waste tank clean and sanitized as well. Sometimes these pests will still show up. But by keeping your RV bathroom clean, dry, and as bacteria-free as possible, you can eliminate a problem before it exists.

However, if you find that gnats have invaded your bathroom, there are a few things you can do to get rid of them. Let’s take a look.

Dilute Your Black Tank with Bleach

Diluted bleach and non-chlorine bleach are safe to use in your black tank. Odors signify bacteria, which means a breeding ground for those tiny bathroom flies. You must clean out your black tank to get rid of the bacteria and protect your RV. Using too much chlorine bleach can harm the seals and gaskets and kill good bacteria. So by diluting the bleach, you’ll safely sanitize your black tank.

Usually, this means combining a quarter cup of bleach with a gallon of water, although this can vary depending on the size of your black tank. Always wear gloves and protective glasses when using bleach. Empty the black tank entirely and then empty the gray tank to flush out any residual waste.

Hurry Up and Wait

Fill the black tank to about ⅔ full with water by flushing your toilet. You can sanitize the black tank now with the diluted bleach solution. Don’t leave it in the tank any longer than 10 minutes but long enough for the solution to break down any waste left in the tank and break apart the bacteria growing inside.

Drain and Rinse

Keep draining and refilling the black tank as long as necessary to get rid of the odor. Once complete, fill and flush the toilet a few times to fill the bottom of the black tank. If you skip this step, the first waste that goes down will get stuck to the bottom of the black tank and may not drain properly.

Can You Get Rid of Bathroom Flies Without Bleach?

If you’d rather clean the black tank with a natural solution rather than bleach, it’s possible. You can use a baking soda and vinegar solution followed by boiling water. First, clean the drain with an appropriate cleaning tool.

Next, pour half a cup of baking soda and one cup of white vinegar down the drain. Leave the solution for 15-30 minutes. Then pour a gallon of boiling water down the drain to thoroughly flush out any remaining bacteria or waste.

You can also get rid of sewer flies by using an apple cider solution. Because these insects are attracted to the smell, you can use it as bait to trap them. Pour a quarter cup of apple cider vinegar in a bowl, cover the bowl tightly with plastic wrap, and poke holes in the top. Place the bowl near the drain to trap the flies and gnats. They’ll be able to get in, but not out.

How to Keep Your RV Bathroom Fly Free

It’s crucial to keep your bathroom and kitchen clean. By removing waste and bacteria, you’re getting rid of food for insects. They won’t lay eggs where there isn’t food. Keep the RV bathroom and kitchen dry, also. And properly maintain your black and gray tanks to keep waste build-up from attracting gnats and flies.

Stay On Top of Cleaning to Prevent Bathroom Flies

It’s easy to keep flies away, but you have to stay on top of cleaning your RV – especially the bathroom and plumbing. Sometimes pests show up even after a thorough cleaning, but if you can keep your home on wheels sanitized, and free of bacteria, you’ll be doing what you can to prevent infestations and problems. Keep your tanks on your regular maintenance list, or you’ll regret it later. When’s the last time you cleaned out your black tank?

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  1. Susan Johnston says:

    I have Never heard of cleaning / sanitizing the black or gray tanks…..and I’m a clean-freak! Is there a schedule for that? Once a year? Once a month?
    Great article!

  2. Del says:

    Very useful article about the flies. You think you have problems! I stopped by the Oregon Wild Horse and Burro Corrals
    just east of Hines, OR which is just east of Burns, Oregon a couple of days ago and enjoyed a very nice “auto tour” with my 26 foot Coachman. It is a very well maintained road that encircles the corrals. You could take about any size RV on the road and see the many horses and some burros that they are keeping and getting ready for adoptions. I wanted to get a little better photos than I was getting through the window, so I got out a couple of times to get a direct view to the different herds of horses, as well as their colts. As clean as the place is, when I drove off, I discovered my RV was FULL of flies. I’m talking hundreds and I couldn’t get them leave. I drove the rest of day back to Boise with the cab windows up and down over and over to try to get the flies close enough to the windows to get sucked outside. Nothing worked. I thought I might have gotten at least a lot of them out, but when I went out to the RV to clean it up the next morning, it was again FULL of the little critters. They were all over the windshield and inside the living area. It took ages to chase most all of them out. I hope I was successful, as I put the RV away for the Winter. I will most likely find plenty of dead ones this coming Spring.

    The BLM Horse Corrals are really something to see if you are at all interested in horses. The corrals are open about
    8 AM to about 3:00 PM on Mondays through Fridays at this time. If you are in the area, it is well worth seeing and
    is free. Maybe you’ll want to take a somewhat spirited horse back home with you? I’ve passed this place many times
    over the years, not realizing it was open for visitors for no charge. You will know you are there when you see the large
    cut-out horse on the hillside on the north side of Highway 20. Also, you can’t beat the beauty of the wide open spaces
    of the high desert between Vale, OR and Bend, OR.

    If you are in the area, here is their address and contact information.

    Oregon’s Wild Horse Corral Facility
    26755 Hwy 20 W, Hines, OR 97738
    (541) 573-2930 (541) 573-2648

    Also you can go to (866) 468-7826

    NOTE: And if you open your windows or doors, don’t say I didn’t warn you. You will pay for it.

  3. MARY WHEELER says:

    I just watched a utube video on the black/grey tank cleaning frequencies and they said if you are a full time rv’er your tanks should be cleaned every quarter, if just once in a while use, twice a year.