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Author Topic: small flies coming up through the sewer tanks  (Read 6250 times)

tck

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small flies coming up through the sewer tanks
« on: April 14, 2009, 07:07:43 PM »
Can anyone tell me how to rid myself of these midget flies.  They seem to be coming through the toilets or holding tanks.  The tanks are closed and have water and the tsp stuff in them.  I have recently flushed the tanks and cleaned them.  I do this on a weekly basis while in the coach.  I sure hope that someone will have a remedy for this.
Thanks.
TCK

Pat723

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Re: small flies coming up through the sewer tanks
« Reply #1 on: April 14, 2009, 07:30:12 PM »
tck

The best way I know how to get rid of the flies is to.

1 Rinse the tank out with tank rinser on the outside of your unit, or if the stool does not have a trap in it try and rinse with pressure water the tank walls from inside the stool,    don't forget the rubber gloves. And then drain the tank.

2  Then fill the tank with water and use 1/2 gal of bleach let sit for a day or so if you can.

What the problem is that your sewer tank is not getting all the way clean.
Also when I travel, I dump before leaving if possible and put some water in it to splash around to clean the walls of the tank while driving down the road

Pat
Drive it like you stole it
Get out of my way I'm going camping.

Ron

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Re: small flies coming up through the sewer tanks
« Reply #2 on: April 14, 2009, 07:57:20 PM »
Never Never use bleach in the BWT.   If we had such a problem we would add regular Dawn dish soap, Fill the tank, add Roebic K-67 and let it set at least 24 hrs then drain.
Ron & Sam-home is where we park it. Currently located   HERE

Pat723

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Re: small flies coming up through the sewer tanks
« Reply #3 on: April 14, 2009, 08:04:03 PM »
Ron

Why not bleach ???

Pat
Drive it like you stole it
Get out of my way I'm going camping.

BernieD

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Re: small flies coming up through the sewer tanks
« Reply #4 on: April 14, 2009, 08:16:42 PM »
Why not bleach ???



Pat

The bleach kills the enzymes that are part of the septic process in the holding tanks.
Bernie & Marlene Dobrin
Home is Goodyear, AZ
Missing our Travel Supreme

Pat723

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Re: small flies coming up through the sewer tanks
« Reply #5 on: April 14, 2009, 08:32:18 PM »
BernieD

I understand what you are saying.
But it is a holding tank not a septic tank.
Not trying to cause a argument here, so do not take it personal just my thoughts

Pat
Drive it like you stole it
Get out of my way I'm going camping.

Mick & Pat

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Re: small flies coming up through the sewer tanks
« Reply #6 on: April 14, 2009, 08:33:11 PM »
Are you sure these black flies are entering your RV via the black tank?

A few days ago we kept getting small black flies in our shower cubical so I place a rubber plug over the drain when the shower wasn't being used and the flies stopped.

I'm presuming that they are entering via the 3" sewer pipe which because of no U bent is open to the elements
Regards Mick & Pat Podmore.

UK couple who toured USA / Canada. Oct 2007 - Aug 2009

2005 Fleetwood Discovery 39S,Cat C7, Freightliner XC Chassis  2008 Jeep Liberty Ltd 3.7 .

Ned

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Re: small flies coming up through the sewer tanks
« Reply #7 on: April 14, 2009, 08:43:47 PM »
The flies are very likely coming from the campground septic system, not from your holding tank.  Arrange your sewer hose so it has a loop in it, like a P trap, that will stay filled with liquid and that will keep the flies from getting into the holding tank.

And yes, it's a holding tank but there still is a bacterial action taking place that breaks down the solids.  That's why you don't keep the drain valve open on the black water tank, to let the bacterial action do its work.
« Last Edit: April 14, 2009, 08:45:20 PM by Ned »
-- Ned -- Fulltimer 1997-2013
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Ron

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Re: small flies coming up through the sewer tanks
« Reply #8 on: April 14, 2009, 09:05:04 PM »
Bernie and Ned are correct.  Kill off the natural bacteria and you will have serious odor problems.  Let nature do its job and all will be well.  When you hook up to sewer make a trap to keep the bugs from flying up into your grey water tank.
Ron & Sam-home is where we park it. Currently located   HERE

BernieD

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Re: small flies coming up through the sewer tanks
« Reply #9 on: April 15, 2009, 05:24:15 AM »

Not trying to cause a argument here, so do not take it personal just my thoughts


Pat

No argument, nothing personal. Just the facts :D :D
Bernie & Marlene Dobrin
Home is Goodyear, AZ
Missing our Travel Supreme

Chet18013

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Re: small flies coming up through the sewer tanks
« Reply #10 on: April 15, 2009, 06:21:44 AM »
Sewer flies are common in quite a few municipal systems. Some septic systems will have them also. The most obvious way into your tanks is via your dump hose. If you wish to get rid of them, just make sure you flush your tanks good and NEVER leave your sewer hose connected. I have seen many RVers who feel the first thing they must do upon arriving at a camp ground is hookup and open their gray--and occasionally black water valves. This just invites an invasion of the sewer flies, if they are in the system. More than once, I have been getting ready to dump, taken the cap off of the camp ground dump and seen it covered with sewer flies on the underside.

The only time my dump hose is connected to a campground site hookup is when I dump.

If you are there for an extended stay, Ned's suggestion of a loop in the pipe is good insurance.

Chet18013
Chet18013
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towing a 2014 Jeep Grand Cherokee diesel

chick a dee

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Re: small flies coming up through the sewer tanks
« Reply #11 on: April 15, 2009, 08:52:09 AM »
tck:

Had same small fly problem you described. Flies would come out of the stool drain as it flushed. These were VERY tiny and just a bit bigger in appearance than fruit flies.  ANYWAY....after trying ALL solutions mentioned here, with NO success, we finally ended up buying a simple spray can of Raid brand "Flying Insect " killer, and...after dumping black tank, and flushing as usual, and after adding our usual amount of water to the tank (4-5 gal.), I then opened the flush gate between toilet bowl and drain down to tank, and holding the spary/fogger can close to the inlet into the drain I sprayed (fogged) 3-4 times down the drain at about 2-3 seconds each time, then closed the gate. To preclude possibility that the fog/spray might damage the gate and/or drain seals or plastic, I then flushed the toilet through it's usual three flush cycles, and......WE HAVEN'T HAD A FLY SINCE!!!  It's been about a month now, so it seems to have made a BIG difference.  Steve & Lynette

tck

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Re: small flies coming up through the sewer tanks
« Reply #12 on: April 15, 2009, 10:50:14 AM »
Thanks to all for your suggestions.  Will probably try them all and after a full dosing they will be gone.

annekeller3

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Re: small flies coming up through the sewer tanks
« Reply #13 on: August 26, 2013, 09:55:38 PM »
I hope this comment is viewed as it falls in line with this subject.  I got online to locate a one way valve to stop the flies from coming in or anything else for that matter.  We live in our fifth wheel and leave the gray water valve open all the time.  And are plagued by those pesky little black flies.  Not in copious amounts, just enough to be annoying.  So I figure this must be a regular problem.  I could find valves like to replace the valve to dump, but no one way valve that allows liquid and solids out, but all can only go one way, another check valve of sorts, but one that doesn't need to be opened or closed since it will allow the above to freely flow one way.  Does not such a device exist?

Lou Schneider

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Re: small flies coming up through the sewer tanks
« Reply #14 on: August 27, 2013, 02:52:38 AM »
Welcome to The RV Forum, Anne!

As far as I know, a one way drain valve doesn't exist.

If you're going to leave your grey water valve open, make a low spot in your drain hose that can fill with water and form a water seal against fruit flies, etc.  It's the same principle as the P traps underneath your sinks.

Personally, I like to leave both my tank valves closed and only open them when I'm ready to dump.  I find my grey water tank needs to be dumped about twice as often as my black, so every second time I go outside to open the valves I open two instead of one - the black tank first, then the grey to let the grey water flush out the hose.
« Last Edit: August 27, 2013, 02:55:00 AM by Lou Schneider »

annekeller3

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Re: small flies coming up through the sewer tanks
« Reply #15 on: August 27, 2013, 07:03:12 AM »
I really appreciate your information.  I am currently using a macerator to remove all in the black tank. I saw a youtube video about a "non return valve". Almost looks like a pressure reducer.  It is used in plumbing to restrict water from going both ways. It would fit a 1" pipe setup like I have, just not so sure about the small chunks. Ever since I almost flooded the RV when my mother in law was visiting and the gray water started coming up the drain while she was in the shower have I left the gray valve closed.  I do like the idea of flushing the line, but with the macerator pouring water down the line, it does get a flush, and I don't run out in a towel to open the gray valve because I forgot.

annekeller3

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Re: small flies coming up through the sewer tanks
« Reply #16 on: August 27, 2013, 07:11:20 AM »
Without closing and possibly forgetting to open before creating a mess, the black tank has a flush, is there a way to flush the gray tank other than dragging in a hose into the sink?

Ned

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Re: small flies coming up through the sewer tanks
« Reply #17 on: August 27, 2013, 07:21:58 AM »
There is really no reason to flush the gray tank.  Much of the water that goes into it has soap in it and that tends to keep it somewhat clean.  And there should never be any solids put into the gray water tank, just drain water.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Want to know what we're doing? http://blog.usabyrv.us

Gary RV Roamer

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Re: small flies coming up through the sewer tanks
« Reply #18 on: August 27, 2013, 07:45:42 AM »
You can put an internal tank sprayer on the gray, just like the ones used on the black tank in many RVs. Many upper end motorhomes come with gray tank sprays these days. I don't think they are necessary, even though I have one (standard equipment), but some people like to think of their tanks as "clean" and use them religiously. I even know a guy who rigged his to flush with hot water - says it does a better job!
Gary
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Great Horned Owl

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Re: small flies coming up through the sewer tanks
« Reply #19 on: August 27, 2013, 07:59:16 AM »
The correct answer is that they are drain flies. They are small aquatic flies that breed in water. Once established, they will even breed in the traps under your sinks or shower. See http://entomology.cornell.edu/cals/entomology/extension/idl/loader.cfm?csModule=security/getfile&PageID=858411 or http://en.wikipedia.org/wiki/Psychodidae or http://www.orkin.com/flies/drain-fly/ for treatment and prevention methods.
« Last Edit: August 27, 2013, 08:01:46 AM by Great Horned Owl »
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