We configured the hookups for our Wolf per the manual, but the shut-off was not as simple: code wanted it very near the range (one suggestion was in the back of a cabinet next to the range), but common sense was to put it futher away from the range. If the gas was being cut off for routine work, then it didn't matter how close the cut-off was to the range, but in an emergency it seemed nuts to have the cut-off very close to either where a fire was or a flash point for leaking gas would be. Since we were running a new line for the range anyway, we have a range cut-off in the basement (it's very nearby the kitchen).

Sophie's route is undoubtedly safer, OTHO the only way you learn how to DIY projects is by doing them, whether or not you already know how (with the required reading, youtube videos and other preparation, of course). Sometimes it comes out so badly you need to rip it out and try again, sometimes it comes out OK and you will do better the next time, rarely it comes out great. The important thing is to learn. Education is expensive, whatever form it takes. I don't regret the projects I did with disastrous results and then had to re-do, because now I've done similar things 20 or 50 times and can do them correctly, and with confidence. If I hadn't done it the first time I would never have learned anything. It's all a question of where your interest lie.

So I am going to disagree a bit. My main piece of advice - Don't assume that what you believe is true just because you believe it. Something isn't bad just because you think it is bad, and something isn't right just because you believe it is right. You are building a home, it is going to be a great home or a terrible home because of the knowledge and actions of professionals, and not because of what you believe. Many many years ago I had a plumbing license, I am not an expert in plumbing by any means, but from the time I was 13 years old, I spent summers and weekends working for my dad's plumbing company. There is not nearly enough information to answer your question in any meaningful way. Waste plumbing running horizontally sloped isn't a problem at all. I assure you that there are many spots that plumbing runs through a horizontal slope for stretches much much longer than 7 or 8 feet. Additionally, PVC running 8' through a wall is not necessarily going to harm anything in the wall at all. Nothing. The typical master bath today will have wall runs longer than 8', even through 2x4 walls. If you want to post a floorplan and describe where the pipes are and their diameter, I can give you more advice. Generally, putting a toilet or tub/shower outlet in the wrong place is a problem, while putting sinks in the wrong place is usually not a problem, putting the stack in the wrong place might be a problem and it might not be a problem at all. The plumber probably COULD have dug this up, fixed it in the ground, patched the slab and gotten on with it What you are describing may do more harm than good. Every plumber, who has been doing this for more than a few months, will have quickie sawed through a slab. Sawing through an uncured concrete slab isn't even a lot of work, so there is little reason to believe that either party were avoiding this if it was the best solution. Lots of plumbers don't like a lot couplings and joints in a concrete slab in 1.5" or 2" pipe. A clog in the slab is costly. As for the mistake. Mistakes get made in builds, it just happens. A good builder will protect the homeowner from the mistakes. However, he is not going to call you every time a mistake that is easily correctable gets made. In the scope of things this just isn't necessarily a very big mistake. With some more information I could give you an opinion. If you are that concerned pay a plumber to come look at the house and give his opinion or post actual pictures of the mistake and the floorplan.

To help everyone understand extent of work, it will help if you provide home square footage, # of bathrooms and fixtures, # and type of water heaters, if you have a preference for copper or pex, if plumbing is going to.be in a slab, crawl space or ceiling etc etc. This is not an exhaustive list of questions but a sample list. Just to give you an idea, for our very large home and due to economy of size, it worked out to around $3/sf for basic plumbing/piping and labor. Fixtures another $3/sf, not including water heaters. A smaller home may end up a litte more per sf.