# Septic Flies



## SCRich (Feb 27, 2008)

I went to another forum and asked but apparently no one there understands what a septic/sewer fly is. 

I have a section of my home which is actually a 2nd home, it beloned to my mother who passed away in Feb. That 1,500sqft section has it's own 2 baths, and kitchen and I am getting septic flies coming in. I run water in all the drains every 2 weeks but apparently that is not enough. 

I had one person tell me to use sponges in the main drain line to seran wrap on the drains...we do go there every so often to clean and that would not be practical. Another person told me to be careful since I have flies that I can get snakes and rats to come in! Come on..my septic tank is not wide open, these are just flies, has no one ever opened their own septic tank at all, it's natural! Is their any other way to prevent this? I know they are normal but with unused drains it becomes a big problem. 

Thanks!


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## Cabin Fever (May 10, 2002)

That's a new one on me. I'd suspect some kind of house flies are laying eggs in the bathroom traps, and after going thru the larvae stage are hatching into flies.

Flies - or any other respirating critter that require oxygen - cannot survive in the septic tank where the atmosphere and liquid contains no appreciable oxygen but plenty of hydrogen sulfide, methane and other toxic gases.


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## Ross (May 9, 2002)

I've worked on septic system before everything from pumping to installing them and I've never heard of such. Perhaps what Cabin says about the traps is right, or maybe they're cluster flies, coming out of the wood work and falling in the drains?


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## SCRich (Feb 27, 2008)

From the Internet
Insects
Mosquitoes and flies can be a problem if they enter and breed in a septic tank. Strangely, this is not often mentioned in literature on the subject. Mosquitoes and flies can enter through the plumbing vent of the house, go down through the 4-inch drain pipe and through the inlet tee to the tank. They can then breed in the tank and travel via the same route, reversed, to the outside world. You can cover the top of the vent with a capper of stainless steel screen. Another place for mosquito entry can be tanks with wood or fiberglass risers; here the manhole covers can be sealed with roof patch or a plastic sheet over the lids, then covered with a few shovelfuls of sand.

http://www.shelterpub.com/_shelter/ssom-maintenance.html

I had to have the tank pumped once and I had a paper plug at the inlet of the tank another time, unknowingly I thought it was a bacteria failure and that the solids tank had filled up so I called in a pumping company. Both times I was there and helped locating the tank and digging up the access lid. Each time I have seen it open there are hundreds of these small flies which are called Phorid flies. I have seen them before, you will often see them near rotting vegtables and I am sorry to say that I have seen them with dead bodies, I was a police officer and EMT for many years and have had the expirience of seeing 2 decomposing bodies in my time.

Anyway 2 different septic companies and both gentlemen where #2 is their #1job both say it's common and natural. Only thing that is not natural is that they start flying into the home. Again I can see it happening if the S trap under a sink dries out but don't know about shower drains since I have never installed a shower (slab construction) do tub/showers and regular showers have a S-Trap underneath ? If not how do septic gases get blocked from entering the home along with these Phorid's ?


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## SCRich (Feb 27, 2008)

OK maybe another thought...seeing we have responses from the Northern latitudes, could it be a regional thing? I have searched the internet and it seems common, plenty of hits but mostly speak about sewer systems and breeding in drains with hair and gunk. The bathroom that these seem to be mostly coming out of has NEVER been used. Such a waste but Mom wanted a 2BA home...it also happens to be the bathroom closest to the drain to the septic. 

I would also question myself thinking that this is not in the tank or normal but again 2 pumping guy's stated it was normal and I saw them myself swarm out when the tank lid was opened. I would think they would be in the drain but again the problem only shows up when the drains are NOT used for a period of a week or 2 and what appears to be "ground zero" for the infestation is a sink that has never been used.


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## Ross (May 9, 2002)

Certainly an interesting dilema! Sorry for your problem but it is. Showers should have some sort of trap for exactly the reason you said. You can snake it and feel for the trap. There's a bacteria mosquito control you use on ponds I wonder if there's not somethign like that for your situation.


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## SteveO (Apr 14, 2009)

I have had it happen. Try vegtable oil about a cup in each drain should do it. you need to keep the traps from drying out. Don't put any water down the drain the oiil will seal it for you.
best
Steve


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## fishhead (Jul 19, 2006)

Or maybe mineral oil. That wouldn't go rancid.

One time my new furnace wouldn't stay running. It would start the exhaust fan but before firing it would shut down. That keep repeating.

When I looked at the drip hose it was full of some kind of pupae. I'm pretty sure it was fly pupae. The furnace was in the basement. Why they chose that spot I'll never know. It hasn't happened again and it's been over 10 years.


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## TripleD (Feb 12, 2011)

I had this same problem on a rental house, but I had pulled the toilet for a new floor. I was painting at the time and had to use a shop vac to get them off the ceiling and walls. I put carpet padding in the toilet flange and filled the sinks and tubs about 2 inches deep with water. After I installed the new toilet they never entered again.


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