small flies coming up through the sewer tanks

[LYNDAPOYSOR]

HELLO,
JUST WANTED TO LET YOU ALL KNOW I HAVE THE SAME PROBLEM LIVING IN A 2002 TRAVEL TRAILER FULL TIME AND HAVE NOT MOVED SINCE 2010. THESE LITTLE BLACK FLIES (LESS THAN A 1/2 INCH LONG) ARE NOT DRAIN FLIES. THEY LIVE IN THE BLACK WATER HOLDING TANK. WHEN THEY FIRST APPEAR IT IS USUALLY CRAWLING ON THE TOILET AND THEN FLYING. THEY ARE ATTRACTED TO LIGHT AT NIGHT AND ARE SLOW ENOUGH TO BE SQUASHED BY HAND. SOMETIMES THE BLACK-BLUE LARVAE (LEGLESS SLUG) MAKES IT ONTO THE BATHROOM FLOOR NOT FAR FROM THE TOILET. I AM IN THE PROCESS OF TRYING ALL THE REMEDIES. THIS IS MY THIRD YEAR IN A ROW DEALING WITH IT. THIS YEAR I AM DETERMINED TO RID MYSELF OF THE MENACE. REPORTS SAY THEY COULD CAUSE DISEASE, BECAUSE OF THEIR ORIGIN.
OTHER TYPES AND SIZES OF FLIES MAY ALSO CAUSE OTHER PROBLEMS.
WHEN I FEEL THEY ARE GONE, I AM ALSO GOING TO MOVE ON TO THE enzyme-based, formaldehyde-free additive SOLUTION, IN THE HOPES THAT WILL STOP THEM FROM RETURNING.
RESPECTFULLY,
L. POYSOR

 

[Gary RV_Wizard]

I don't think any holding tank chemical is going to affect the sewer flies.  With a 3-year problem, I think I would flush the tank well and then fill with a fresh water containing 10% bleach and let it sit a couple days before emptying. Hopefully kill of the larvae. Not sure how resistanat those larvae may be to bleach, though.

You may have a "poop pyramid", some accumulated solid waste that doesn't flush out. The larva will burrow into that and stay fairtly safe from pesticides or chemicals. The solution is to get the tank clean.

I don't know if this page has helpful advice or not, but am passing it on:
http://www.getridoffliesguide.com/how-to-get-rid-of-drain-flies/

 

[garyb1st]

Had this problem when we got back to the RV yesterday.  Did a quick Forum search and nothing.  Then found this thread doing a Google search.  Obviously we're not alone in this problem since the thread has been read more than 13,500 times since first posted 6 years ago.

I rinsed the black tank until the water was clear.  That seemed to have solved the problem.  Keeping my fingers crossed. 

Some great advice here and while I never keep the drains open, I do leave the hose connected from time to time.  Not anymore and if I do, I'll keep the hose looped creating a trap. 

 

[Gary RV_Wizard]

The flies may come back - they typically leave eggs in the slime in the tanks and a new hatch repeats the problem. May have to repeat the flushing. Do it quickly, before another generation gets going!

 

[Arch Hoagland]

http://www.homedepot.com/p/Bayer-Advanced-32-oz-Concentrate-Carpenter-Ant-and-Termite-Killer-Plus-700310/100638302

I use this everywhere around my house and actually spray the bottom of my coach and water heater/refrigerator compartments.

I believe if you added several ounces to your black water tank and drove around a bit it would take care of the problem.

One thing about this stuff is that it doesn't smell. Most bug sprays smell. 

 

[motojavaphil]

I had the same issue with the flies.  My fix was to fill the BW tank completely full with some Dawn and water on days we knew we would be away.  It would sit for the day and upon return we would drain it followed by a good dose of grey water.  The guages even began to work.  The idea was that the tanks are designed to be holding tanks and if they hold nothing or very little other things take up space in such a rich environment. 

 

[jamifids]

I've been trying to get over these flies for 3 days now! We're on a trip, so I can't spray or treat them. We just kill them, but there are no fewer of them. What should I do?

 

[Rob&Deryl]

I've been trying to get over these flies for 3 days now! We're on a trip, so I can't spray or treat them. We just kill them, but there are no fewer of them. What should I do?

Maybe close the tank valves, let the tanks fill, then dump them all?

 

[Great Horned Owl]

They're Drain Flies, annoying but harmless.They breed in your drains, often the kitchen sink drain. See Drain Flies

Joel

 

[Kirk]

I've been trying to get over these flies for 3 days now! We're on a trip, so I can't spray or treat them.

Are they ordinary house flies or possibly sewer(drain) flies?

 

[JudyJB]

Why can't you treat them on a trip? I keep a spray bottle of flying insect killer in my utility compartment. The couple of times I have found flies when starting to hook up, I have sprayed down the sewer pipe and in my drain hose.

Also, you can treat your kitchen, bathroom, and shower drains by pouring down a kettle of boiling water in each every couple of days until they are gone.

You can also dump down some diluted liquid flying insect chemicals and then drive around to slosh things in your tanks. You want to add enough liquid so that the drain pipes get a coating, plus leave some in the tanks for a while.

 

[Viajeros]

Happened a few times over the years. Usually in summer. Fill it up and flush it out. It’ll be fine.

 

[billwild]

We would leave our trailer in Arizona in the spring and return in the fall. Our water pressure would then be low. Found out we were not plugging the hose connection on the side of the trailer and flies would enter there and die and plug the water line. Bought some new plugs and all is well again. Darn flies!!

 

[jamifids]

Are they ordinary house flies or possibly sewer(drain) flies?

sewer flies(((

 

[jamifids]

Why can't you treat them on a trip? I keep a spray bottle of flying insect killer in my utility compartment. The couple of times I have found flies when starting to hook up, I have sprayed down the sewer pipe and in my drain hose.

Also, you can treat your kitchen, bathroom, and shower drains by pouring down a kettle of boiling water in each every couple of days until they are gone.

You can also dump down some diluted liquid flying pests chemicals and then drive around to slosh things in your tanks. You want to add enough liquid so that the drain pipes get a coating, plus leave some in the tanks for a while.

My wife is allergic to these insect repellent chemicals.