Opening sewer line cleanout
My residential 4" (PVC up to the 90 degree clean out fixture that goes out of the house which is cast iron, metal in any case) sewer line appears to be clogged in the line going out of the house to the septic tank, where there is a baffle that can trap stuff like toilet paper. I tried to open the clean out which has a square "nut head" on the "cap". The only tool I have with a large enough "mouth" is a pipe wrench, which I tried. The biggest one I have is a 15" long one and I couldn't budge the cap. I see a 21" pipe wrench at Lowes, but hesitate purchasing it if that isn't the tool I should be using.
I will appreciate any tips on how to break into the clean out without breaking it. My choice is to dig up the septic and see if the clog is at the baffle, which I think it is.
I dumped a 1/2 gallon (or there about) bottle of Liquid Plumber about 2 hours ago and will see what happens in the next couple of hours.