There should be an opening on the top of the outlet pipe, just below the septic tank lid, which would put it about 10 above the water level. The only way solids can get into this opening is if the tank overflows due to a plugged outlet baffle. This is an air vent to keep the outlet pipe from becoming air bound and not allowing water to flow out of the tank. : We just had our tank pumped. We had a blockage in the : inlet. The guy who pumped the tank tried to clear the : blockage, but couldnt. After he left, I dug to the : inlet pipe, opened it up & cleared it out. Now, when I : looked inside the tank, I saw at the outlet side a large : ragged hole (maybe 8 inches dia.) in the outlet pipe, near : the top. I asked the guy (on the phone, I wasnt there : when he worked on the tank)what was that hole doing there; : he said it was an air vent. Is that really so? It is : about 18 below the top of the tank. It looks to me like : he knocked the hole in it, as he said he tried running : a snake out to the distribution box, and Im afraid that : the stuff on top of the water level will flow into & : block up my drain field.: Anyway – should there be a hole there, or should I try : to patch it up (before the tank refills!)?
