Correct way to check for sewer pipe leak

[indcoltsfan32]

My wife and I built a house approx 5 years ago in central FL. After living in it just after a year we started noticing a huge problem with phorid flies (sewer flies) inside the house. So we had a septic company come out and we found them inside the septic tank and sewer lines (thousands of them). So we had the septic tank pumped and the problem went away for about two weeks but came right back. I am tried everything to get rid of these things to no avail. The only thing I haven't checked so far is a sewer line break/leak. I did alittle research and bought one of those inflatable plugs, stuck it in the clean out and inflated it. Filled up the sewer lines from the tub until the water started coming in from the lowest drain in the house (low shower in master bath). I let that fill up to one of the grout lines in the shower for a reference point and let it sit for approx an hour. Came back in and the water had dropped quite a bit (approx 10 gallons in an hour) and its not leaking past the inflatable plug. Can i assume the water is leaking from a sewer line break?

We have been having a huge issue with these flies for the past 4 years, through out the entire house.

 

[frodo]

you need to hire a plumbing company to do a smoke test

they will cap off your vents and drop a smoke bomb in your pipe
then look for escaping smoke

 

[indcoltsfan32]

I purchased a smoke machine and plan to try that next. If I can at least say there is a good possibility for a leak, I will hire a plumbing company to professionally check it. Ive had it checked once with a camera, but I dont think its a big enough leak that a camera will catch it.

 

[frodo]

you are on the right path
lets us know what you find

 

[phishfood]

Lots of variables in this equation.

If the (possible, let's assume for the moment that it exists) break in the sewer line is below the concrete level, then how do the flies get out of the break, and then up through the concrete?

If the (possible, assuming for the moment that it exists) break in the sewer line is above the concrete level, and it was leaking during your test, then it seems that you would have seen 10 gallons of water leaking onto the floor?

 

[indcoltsfan32]

From what im reading, they small enough to fit through the smallest crack in concrete, So the plumbing break could be near a crack in the foundation.

I cant imagine where else the 10 gallons of water went (I dumped two 5 gallon buckets of water into the shower pan to fill it back up to where it started). The only place I can think of is under the slab, because I have no water inside the house

 

[CT18]

Also baking soda and vinegar in all your drains will kill off the ones that hang out in the immediate area.