Our old sewer line runs right through our future basement.

Obviously we need to dig that ridge of dirt out as well, so we have to put in a temporary line while we are living in the old house during construction.  Because our old line under the street showed some root intrusion, we are required to replace the line to the sewer main in the middle of the street.  They can do most of this using the trench-less method, but this still requires some digging on both sides of the line.  We also need to replace the “Y” connection to the sewer main.  Here is the street work and the line under the grass strip by the street.

To get from our proper under the sidewalk, they have to bore under it.

The replacement sewer line runs around the edge of our property, to be out of the way of digging.

So far, we think that the elevation of the line at the street level, and the elevation of the line in our basement, presents enough of a drop in elevation to allow us to use gravity feed for the basement. We were somewhat worried that we might have to install a sump pump for the sewer in the basement.

Update:  When they replaced the line under the street to the sewer main, they found that it was completely clogged with roots.