Sorry for posting another question so quick after you answered the first but I had something else I wanted to get your opinion on. This is my first house and I am still learning on how to work simple plumbing jobs. We have a clean-out on the outside of our house so you can access the pipe that runs from the house to the septic tank. About a week ago I decided to take the cap off the clean out to make sure every thing was flowing through the pipe properly, which it was. One thing I thought was odd was that when I took the cap off several little flies came out of the clean out. I mentioned this to a pest control guy and he said this was usually an indication that the pipe is broken. Is this true? I actually flushed the toilet on the opposite side of the house and checked the clean out to see if there was any drop off in water volume, but it was fine. I mentioned it to a local plumber and he said its possible that its and indication of a break but wanted to charge me $400 to run a camera in the pipe. Is it possible they can come in from somewhere like a vent pipe?