Hi.. I am needing to at least partially replace some sewer line. The issue at hand is that at one end of my house (kitchen and laundry) I have some issues with either corroded or broken (or both) 40 year old iron drain pipes under the slab. The main sewer line that runs to the road is on the opposite side of the house, so these lines run all the way across the house under the slab and tie in with everything else. In talking with a plumber, he said an option for me to avoid the whole jackhammering the slab up is to simply run a new line out of the side of the house, down the brick, and into a new PVC 3" line and run that clear around the house, then tie into the existing line close to the house. Is this generally something that is legal for a DIYer to do at his own home legally? The plumber stated that there's no specific code on how deep this line would have to be other than it cannot be exposed. I guess our climate here is such that depth is not all that critical. Basically my plan is to dig this approx 120 foot trench (after locating underground utilities, of course) and laying schedule 40 3" PVC, pitching it 1" per 8-10 feet. I won't be tying into the city's main or anything like that. I simply cannot afford to pay someone $85-100 an hour to dig a trench for me. I'm capable of laying the pipe with the correct pitch and making all the connections properly. I do realize there will be some capping off issues of the old line and re-tying things back into the vent and such, which I'm fine with hiring out. Anything I should look out for or advice on laying the new sewer line for this "gray" water? Thanks.