We had done a remodel of a Western Auto and made it into an Advance Auto. I had ran all the DWV and had it pressurized for 2 days waiting on the inspector. After he came and passed it we finished up. I was there installing the water cooler when the Advance Big Boys from the corporate office showed up. One of them went in to use the toilet and it overflowed. I got a snake and ran it through the line only to have it stop cold! I tried to come in from the outside in the septic tank, same thing. I got my big electric cable snake that I use to remove roots with. Same thing, but I did notice some red clay on the spring. I measured the snake off from both directions and came to a point under a newly poured concrete sidewalk. Damn I thought. I told the GC what I had and after quite some time of going over it with him we both came to the conclusion that the stoppage was under the sidewalk. Great. I am responsible now. I got a concrete saw and commenced to cutting. I got down about 2 feet and pulled up a BIG chunk of pvc. I showed it to the GC and showed him the clean white along the fractured edge and said I bet it was broken. Thats when he told me that the electrician had a contractor come in and dig a trench to install his power line for the parking lot lights. After I dug some more I found the 2 ends. There was a 6 foot piece missing of 4" SCH40! The GC called the guy who dug and he swore he never hit anything. BS! Because someone had to have shoveled in the dirt and get rid of the rest over pipe. Lucky for me the GC said to bill him for the extra work and he would get it from the back hoe man.