nicktheplumber
One option that you should consider is the so-called “trenchless” sewer. This involves digging a hole at the far end of the sewer run and at the curb. You cut into the sewer at both ends and snake (with a powerful hydraulic puller) a polyethelene pipe from one end to the other and tie it all in. You may have to dig one or two ther holes along the way to make lateral connections to other house drains. This is a lot easier than digging out a long trench and laying CI pipe all the way. An advantage to PE pipe is that it is seamless and quite immune to subsequent root incursions.
The only caveat is that the PE pipe (which is pilled through the existing clay or CI sewer line) ought to follow a proper slope. If the existing line has a dip in it, the trenchless line will not correct the problem.
Trenchless sewering requires special (expensive) equipment.
NtP
