Septic Tank Baffle Filter Clogging - Sewer Flies?

[skyguy]

Late summer every year, something starts breeding in my septic tank (I suspect sewer flies though I mostly see the larvae). As a result of this, the outbound baffle filter clogs and can cause backup into the house. I know this type of breeding as well is not typically good for septic tank health. I would like to fix this issue so it does not happen year after year.

I am looking for recommendations on root cause and wondering if this has happened to others. I would prefer to fix the cause at the root (as a permanent solution) rather than pouring a chemical mixture into the septic periodically to kill the flies / reset its health.

The lid to the septic tank is concrete and chipped and as a result may not make a tight seal, so flies could potentially get in that way. Potentially they could be breeding in my drains and making their way down in that, though there is no sign of them at all in the house.

Thanks in advance.

 

[haloflood]

How often does the filter clog? How do you know the clogging is being caused by the insects? Is the baffle filter located at the final outlet of the tank before the water goes to the disposal area? How many tanks and/or chambers does your system have?

Making sure the tank is sealed as tight as possible might help (at the very least it can't hurt). Regularly cleaning the filter (if it's removable and cleanable) would help prevent backups.

Otherwise, I'm not sure how to get rid of flies inside a septic tank, though I've seen plenty of them. Flies, cockroaches, albino grasshoppers; you might be surprised how much animal life can be found inside a septic tank.

 

[skyguy]

How often does the filter clog? How do you know the clogging is being caused by the insects? Is the baffle filter located at the final outlet of the tank before the water goes to the disposal area? How many tanks and/or chambers does your system have?

Making sure the tank is sealed as tight as possible might help (at the very least it can't hurt). Regularly cleaning the filter (if it's removable and cleanable) would help prevent backups.

Otherwise, I'm not sure how to get rid of flies inside a septic tank, though I've seen plenty of them. Flies, cockroaches, albino grasshoppers; you might be surprised how much animal life can be found inside a septic tank.

Thanks for the reply.
Filter clogs every ~3 weeks (or enough is in the filter that I clean it to prevent backup issues) in peak summer. Timeline spreads out more into fall and drops off completely in the winter/spring. I have had this issues for a few years running now and only now just deduced that it is caused by the insects - the filter itself is clogged with their larvae, top layer of the septic you can see them moving around and many sewer flies are living in the area between the access cap and septic tank. They die off as the weather cools (I live in the northeast so it becomes cold enough to kill them off completely in the winter time).

This filter that is clogged is the final outlet from the septic tank to a lift, which in turn goes to the leach field. They could potentially be getting in through the vent (there is one with the lift) as well, that has a mesh screen but I'm unsure if they could work their way back into the septic tank.

It is a single tank / chamber septic tank, which was reused--the rest of the disposal system was replaced several years ago (and the baffle was installed at that time). It was indicated that the filter should need cleaning once every 2 years after the first year. I can continue (and will) to clean the filter, but I feel like it is a band-aid on my septic health and would prefer to fix the root problem.

 

[Randy Constan]

I know your post is several years old, but same thing happens to me. I've no clue what the "creatures" are, but I have to clean mine every 2 months. The advise about sealing more tightly might be a clue, because I used to only have to clean it 1 or 2 times/year, but then I made it easier by leaving off the retaining bolts I had added to the cover, opting instead for just a cement weight holding the cover down. And come to think of it, that's when the more frequent cleanings became necessary. Hmmm!!! Maybe I'll try adding some inch thick stick-on foam around the edge next time I clean, and see if its less clogged after my usual 2 month wait.