This is a big job. The sewer line starts in our back yard, about nine feet below the floor level of our house. It travels all the way across the back yard, and then out to the street. Obviously, the pipe has to slope downward the entire way (I believe they say sh*t doesn't flow uphill). So by the time it reaches the street, the pipe will be about 18 feet under ground.
The trench they're digging is quite deep. I would not want to be down in there. Would you?