Flies/fleas in black tank


macamper240

New Member
We are full-timers. A year ago we did some volunteer work at a non-profit that had a large septic system. We started seeing little black bugs coming out of the black tank when we flushed. They kind of hop around, I think the way a flea might. We asked the owners about this and no one knew anything about it. Eventually they agreed to open the cover in one area of the septic system and a huge cloud of these black bugs came out. To make a long story a little shorter, we occasionally still see these bugs. We might go for several weeks without seeing them, then they again appear. We do, of course, use chemicals in our black tank and do not have any odor problems. It seems that these bugs must lay eggs in the black tank and they eventually hatch. We have sprayed all kinds of bug spray down the toilet. We have tried using clorox and filling up the tank with water to clean it out, etc. but we still see them. We've thought about somehow using a "flea" bomb in the tank, but the box that the bombs come in always say not to use in a room less than 5' x 5'. Anyway, you can see we're getting kind of desperate about getting rid of these things.

If anyone has experienced this type of situation we'd be especially happy to hear how you "eradicated" them. Thanks for your help.
 

hertig

Senior Member
Flies/fleas in black tank

Perhaps they are in the gray tank too. Have you cleaned that out thoroughly?
 

macamper240

New Member
Flies/fleas in black tank

Thanks for the reply. Yes, we've also cleaned out the grey tank. We can actually see the bugs come out of the toilet.
 

racefan

New Member
Flies/fleas in black tank

bomb the hell out of them who wants bugs crawling on them when there taking care of buisiness
 

macamper240

New Member
Flies/fleas in black tank

I found out that the bugs we were seeing are called fungus flies. Anyway, we did use a bug bomb in the bathroom with the flusher open. We stuck the bomb down the hole for a minute after we first set it off then set it on the floor for the rest of the time. So far, we've seen nothing else. We will be doing it two more times (every other week) to make sure we've taken care of the eggs that hatch. Thanks for the replies.
 

loonz9

New Member
Flies/fleas in black tank

We had our septic tank pumped a couple of years ago. It is normal, and healthy, to have these little bugs in septic tanks. They help with the breakdown of sewage, according to the man who did the pumping. He was happy to see them - meant everything was working properly. They are definitely not a problem.
 

BobW

New Member
Flies/fleas in black tank

Just how do you think the bugs are getting in the black tank? I would guess down the vent. Put a screen over the vent or your going to have these guys in the RV.
 

AnotherRookie

New Member
Flies/fleas in black tank

What you are talking about may be drain flies. One way to tell them apart is to smear one on a sheet of paper. If they leave a dark powdery streak on the paper, they are drain flies, not fungus gnats. Both, however, do live on decaying matter. The reason you are seeing them appear in a cyclical manner is probably that you are seeing distinct generations. When you spray them you can only control the adults. By the time you see them, they have probably already laid a few eggs. Any larvae that you can't get to or unhatched eggs are unaffected. I would suspect thatyou see them are a little more frequently when it is warmer. I would suggest cleaning out your tank thoroughly. Add a little Calgon to the tank according to the directions given for laundry use to help deposits on the sides of the tank let go. Do the Clorox soak, but put some soap in the solution to help the clorox soak into any hardened deposits. Don't forget to disinfect your sink traps since they can do very well around the edges of the water in the bottom of those. Do this every 2-3 weeks for about 6 weeks whether you see the insects or not. This is a bit of a pain, but none of this stuff is very expensive.

If you go back to the place with the problem in the septic system, suggest that they get their tank cleaned. Don't hook up until you have a pretty full tank and are ready to dump, and unhook immediately afterward until you have a full tank again.
 

AnotherRookie

New Member
Flies/fleas in black tank

What you are talking about may be drain flies. One way to tell them apart is to smear one on a sheet of paper. If they leave a dark powdery streak on the paper, they are drain flies, not fungus gnats. Both, however, do live on decaying matter. The reason you are seeing them appear in a cyclical manner is probably that you are seeing distinct generations. When you spray them you can only control the adults. By the time you see them, they have probably already laid a few eggs. Any larvae that you can't get to or unhatched eggs are unaffected. I would suspect thatyou see them are a little more frequently when it is warmer. I would suggest cleaning out your tank thoroughly. Add a little Calgon to the tank according to the directions given for laundry use to help deposits on the sides of the tank let go. Do the Clorox soak, but put some soap in the solution to help the clorox soak into any hardened deposits. Don't forget to disinfect your sink traps since they can do very well around the edges of the water in the bottom of those. Do this every 2-3 weeks for about 6 weeks whether you see the insects or not. This is a bit of a pain, but none of this stuff is very expensive.

If you go back to the place with the problem in the septic system, suggest that they get their tank cleaned. Don't hook up until you have a pretty full tank and are ready to dump, and unhook immediately afterward until you have a full tank again.
 
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