[img]https://cimg0.ibsrv.net/gimg/www.doityourselft.com-vbulletin/731x1145/debcab2c_3965_4994_89df_0b54ab4e0bfe_31001f5bc2d7df286f703e34aedcb42cc636d2ed.jpeg[/img] Adding a half bath to laundry room as pictured below. On a slab foundation and don’t want to cut up the slab if at all avoidable. Will need a macerating/pumping toilet anyways because the drain on this side of house isn’t big enough for a toilet drain. my question is how to get the plumbing along the wall to the sink (it is an exterior wall). The supply lines is on and that macerating unit will be on the same wall as the w/d. If I’m reading codes correctly, I cannot run 1.5 inch pipe through the 2x4 studs on an exterior wall (or I can run through 2 sets of studs if doubled up. Can I run 1.25 in pipe from the sink instead of 1.5 inch so we can run it through the studs? If not and I have to run it inside the room do you have any suggestions on how to hide the pipe? Is it OK to run the supply line through the exterior wall? It’ll be about 4 feet at most and the wall is protected from wind. We can insulate the pipe in addition to the insulation. any other suggestions?

I'm running 3 inch pvc pipe 20 foot horizontally from my toilet to my septic drain. From the beginning to end of my first 10 foot length I should have a 2 1/2 inch drop from my floor which will give me a 1/4" pitch, I add a coupling and another 10 foot length and I should have a 5 inch drop at the end of my 20 foot right? I have a 4' digital carpenters level which has a angle mode I can set for 1/8, 1/4, 3/8, 1/2, etc, right now my pipe is temporally hanging with a drop of 5 inches from beginning to end at 20 feet which should be correct for a 1/4 inch pitch. I put my carpenter level on and it's only showing an 1/8 inch pitch, I'm not sure if I should go with my 5 inch drop at the end of 20 feet or go by the level, is a carpenters level different from a plumbers level for showing pitch?