Ok-- here is my problem. The toilet started draining really slow and not flushing solids. The toilet bubbles when water is ran in sink and vice versa. I called a plumber and they sent a really young guy (no master plumber). He snaked the toilet and didn't find anything. He took the waterhose and ran water down the system and said the water was not backing up. Then he replaced the toilet and everything worked great-- for two weeks. Then he came back and removed a pipe from under my sink and then the toilet started flushing. He said this meant it was a venting problem. He couldn't find the existing vent so he went under the house and installed a new one under the house and took it out the crawl space and up the side of the house. After this the toilet flushed for one day-- then quit again. (I later found the original vent.) Next he said the pipes under the house needed to be replaced and slanted in a different way. After finishing this the toilet flushed two times and then quit again. Where do I go from here? Yes, I plan on calling and asking for a master plumber. What does the problem sound like? PS--I have a septic system.