Is it a good idea to reroute pipes for a 12 unit building rather then take the chance of digging up concrete parking lot and plumber not finding where break in clay pipe is? If there is a break in the pipe at all how can you put a liner in if you can't see?? I personally think the plumber is lying because my backup problems don't happen all the time. 3 times in a 4 month period. And when it does backup from my floor drain its about the amount of water from 2 toilets. Before the backup occurs bubbles came from toilets and then water dissappeared from 2 toilets? Is this the water that comes out of my floor drain?

Is it a good idea to reroute pipes for a 12 unit building rather then take the chance of digging up concrete parking lot and plumber not finding where break in clay pipe is? If there is a break in the pipe at all how can you put a liner in if you can't see??? I personally think the plumber is lieing because my backup problems dont happen all the time. 3 times in a 4 month period. And when it does backup from my floor drain its about the amount of water from 2 toilets. Before the backup occurs bubbles came from toilets and then water dissappeared from 2 toilets?? Is this the water that comes out of my floor drain??
Bad I guess

Is it a good idea to reroute pipes for a 12 unit building rather then take the chance of digging up concrete parking lot and plumber not finding where break in clay pipe is?
Luv made a good guess. I'm amazed that the plumber didn't send a camera through the line to see what's up down there. Don't do anything until you know for sure just what you're facing. Yes, the sewer line can be sleeved without tearing up the parking lot but first you have to get your ducks in a row and know exactly what you're dealing with. If your plumber can't handle this then get another plumber. Good luck, Tom