Recently we have been having a few fruit flies in our RV.
There is only one problem though. We don’t have any fruit lying around. We freeze all of ours. Sheri uses it to make me 100% fruit smoothies – more on that later – I’ll post her recipe. I actually feel better when I drink them.
So they aren’t fruit flies.
How to identify RV drain flies
- They are about the size of fruit flies.
- They seem to be congregating in the bathroom.
- They even seem to emanate from the bathroom.
- That ain’t fruit in the bathroom Dorothy!
Oh oh.
So before I go further, I have to digress.
People have to live.
They eat, drink, and breath at a minimum.
As a direct result of those eating, drinking and breathing, we pee, we poo, we sweat, and we exhale. Yet, we are so hung up on stuff we fail to really talk openly about a couple of the things that are about 1/3 of the major operations of our bodies. The rest of this article has to discuss things on the poo/pee side.
You’ve been warned!
Back to those flies.
- I did a little research on the web and I’ve found that there exists such a thing as ‘drain flies’. They don’t seem that uncommon. Here is what I’ve learned in the following bullets.
- People don’t think you should leave your gray water valves open (black should always be closed) even when connected to a septic or sewer. It seems some people think you can.
- I saw mention that if you put a trap (a loop in your drain hose) such that there is no direct AIR path that will keep drain flies out. However, I saw one place that said that the drain fly larvae think traps are ridiculous and can swim.
- I saw mention of insecticides, but nothing very conclusive.
- Someone said drain flies are dirty and carry germs although they probably don’t know. However, knowing where they have been, I really don’t want them flying around my face.
- People in many places spoke about RV toilets with overflow returns having them live in those areas.
- Drain flies can get in your RV if your black tank is vented. Ours is not. Honestly I wished it was. Send me an email if you wonder why it matters.
Here are some links to articles on the subject:
Here is what I did…
How to eliminate RV drain flies
- I drained the black tank immediately.
- I then filled it up and had a modest amount of bleach in it ( I do not use this often as I think it is bad to put in the septic/sewers ).
- We allowed this to sit for two or three days and filled up the tank even more.
- I now keep the gray water valves closed as well as much as possible.
Here is what I’ve noticed.
- Flies are gone.
- Flies have never came back.
Here are my conclusions.
How to prevent RV drain flies from your RV
- Bleach is bad for flies (although I can’t say this was the primary thing that took care of them)
- Draining the black tank often is good
- I can’t rule out that bleach killed the flies
- you SHOULD drain the tank often
- Keeping the gray valves closed is a good idea. (Again, it might be better black tank management that is keeping the flies gone)
Here is one belief I have which I cannot prove : You can get drain flies from the RV park septic. This makes sense to me and I can’t help think it is true.
RV drain flies insecticides and preventative chemicals and sprays
Amber says
Hey I’m glad I came across your page on this matter. My husband children and I travel for his work and we spend quite a bit of time in our Rv. We learned YEARS ago to keep the black value closed unless we are flushing it. However, we still have this issue with these pesky & disgusting fly/gnat creatures. We don’t keep the gray value closed though, could this be part of our problem?? I’m thinking about closing it and seeing how that goes.
We’ve tried bleach in the past but have been weary of using it again as it can be damaging to parts of the system. I’m thinking that maybe another round of bleach may be necessary, heck it’s worth a shot.
What are your thoughts on the Rv fruit fly products meant to be put in the drains ? Have you heard of any success there??
I’m desperate…. And ready to be rid of these suckers.
I’ve also noticed that with winter weather this is a non-issue. They seem to like the warmer weather as far as I can tell.
Thanks So much
Marlan at Rv52 says
I think if you leave the gray closed your flies may clear up. Also they won’t have much opportunity to get into your RV if you are closed all the time. If you do bleach, you are only doing enough to kill the flies so your amount could be very, very minimal – more about flies breathing chlorine than cleaning the tank. But just try keeping everything closed all the time. We never tried the products as we were able to get them managed without.
Vicki Stafford says
As a former USDA Food Safety Inspector I am all too familiar with the dreaded drain gnat. Bleaching the drains are the only thing that will kill them. Here is my battle plan:
1. Put 2 capfuls of bleach in every sink full of dishes you wash.
2. Do NOT put any food residue down the drain…this includes milk from cereal!
3. Make sure your sewer securely attaches. Any gaps will allow flies to invade and procreate.
4. Repeat Daily
Because we are full time in our motor home, I check everyone’s connection. Your neighbors drain knats are yours as well. Hubby bought a hose contraption that cleans out your tanks. Hoping this will just add another layer to my battle plan!
Vicki
Laura Allen says
My TV is hooked up permanently. But is also fixed where I can disconnect. I have all the valves open. Should I close them and which ones.
Marlan at Rv52 says
You should keep your black valve closed until that tank is full. Then you open it up to empty it. I would keep my gray tank closed normally as well even though you will be emptying it quite often. I explain here; http://rv52.wpengine.com/black-tank-rinse-inlet-fifth-wheel-pictorial-guide/
Angel Dauphine says
I appreciate all of this information. When I originally went full time I immediately experienced knats once I parked and was hooked up. I bought the knat apples from Walmart and used those and within one day they were gone! I’ve also heard to put vinegar in a water bottle because the knat will fly in and get trapped (which is how the apple traps work as well). So, after fulltiming for 6 months my Airstream was stored for about 4 months. I started noticing when I would stop by to check on it there would be tons of dead knats everywhere!! I. Talking tons and tons dead! It happened over and over. I learned that when I dumped the black tank before leaving that during travel apparently stuff comes loose which causes it to set. So next time I camped I cleaned the black water tank as much as possible! Flushed and filled with water, cleaned hose from outside and put in the toilet cleaner pouches to let it set. It helped but didn’t prevent them from coming back. There were about 100 dead next time instead of a million!! So now I’m full-timing again. Once I hooked up and opened my tanks it seems like they’re constantly appearing but only in the bathroom. I closed the tanks and put another pouch in to clean it and so far for one evening they’re gone. So, I’ve had them when hooked up and also while in storage. I tried the old apple trap with no luck this time. There is no airflow in the bathroom so it’s too hot for the apple trap…it dries the juice very quickly.
Marlan at Rv52 says
Great feedback! Thanks.
Rae says
Help! My RV is infested with black gnats. I poured bleach & ammonia down the drains (separately ,of course. Different weeks) & it just doesn’t work. I can’t go to the restroom in peace , eat, cook, sleep, or sit! It is just horrible. I am disgusted. I constantly clean, try to keep my dishes dry on the racks (which is hard cus I’m always using my sink). I don’t know how to stress how infested my rv is, while I’m watching tv you just see big and small gnats flying around (GROSS).
I seem to notice them coming from the restroom, so I spray tons of Rad and then I come back to see tons of little baby gnats dead. But the gnats are everywhere and I can’t take it anymore. I thought about bombing my rv but I really don’t think it’ll work because I do know you have to kill the Larva to stop them from coming.
Im writing this post hoping somebody comes across it who can help.
I just purchased this product on amazon called Nemaglobe… ill be putting that down the toilet because it’s supposed to kill larva . I’ll be back to let you know how it goes.
Btw, today is my first day closing my grey tank. Black tank remains closed until clean out.
Cmmt back if you have any suggestions.
Oh and I thought I had fungus gnats cus a muchroom was grossing from my rv rug!! From organic material .. And I read larva feeds off of that as well ! Ugh, I’m going thru it. Today I put peroxide on those mushroom spots cus I heard they kill larva as well…
let’s see.