Just bought my first house, it is a full renovation project. I am working on how to plan the plumbing, particularly the drain lines. This is an 1913 home in the north west so it has some great character to it, but the layout of the basement causes some issues with drain line routing.

There is a 6'x6' pantry off of the kitchen that I am planning to turn into a 1/2 bath. It is easy access for plumbing due to a full height basement and would be perfect. The only trouble is the drain line... This house has two stacks. the main 3" line is in the front right corner of the house and a smaller grey water 2" line is in the middle of right side of the house. The 1/2 bath we would like to add is all the way in the back right corner of the house, so it is all along the same wall. It would be easy except the basement staircase blocks what would otherwise be a perfectly straight run to the stack.

I have looked at this from all angles and the options I have are limited:

Option 1: dig up the 2" stack out of my foundation floor (which also connects to a very helpful floor drain) and reconfigure it to accept a 3" toilet but lose my floor drain in a wet basement. This was my initial plan, except that I don't know for sure there is a 3" connection to the main sewer line, so I may dig it up and then have to pay an arm and a leg to get the connection modified to fit my needs, and still lose my floor drain.

option 2: Run the drain around the staircase, loose headroom, and cause a conflict with the power panel. Unfortunately when the panel was re done about 10 years ago, the put it about 6 inches from the stack in the very front corner of the basement, so if I ran my drain line into the stack, there would be little room to avoid blocking the panel which won't fly. It's possible to connect to the drain line at a knee height level so the panel door could be opened and operable, but I'm pretty sure that would still be considered blocking... I have explored moving the staircase a little but it is not possible without making major structural changes due to the layout.

option 3:This is the option I like the most, I would need to run the drain line out the side wall of the foundation and connect into my stack before it gets to the sewer main. I've read a lot about exterior lines and risk of freezing and have gotten a lot of back and forth opinions on it. Our region does not freeze often, but as I see it that should be irrelevant. The line is no different than any other black or grey lines running out of the house to the sewer and they don't have any issues, I don't see why this would be an issue either.

Thanks in advance for any advice on this.

2" line is not sufficient for a toilet. 3" minimum. If you cannot tie into a 3" line forget that option. Be sure you research clearances around any electrical panel. They usually are wide enough to permit working on your electrical system. I would take photos and dimensions to the Administrative Authority and ask for recommendations. You would require a Permit in most areas of the county for this type of modification. If you seek more answers from this site, upload a drawing and photos so we can see what you are dealing with. All the Best.

Thanks, I am working on the pics and drawings now.

What I meant for option 1 was to dig out the existing drain line and modify it either all the way to the sewer line or if it was shrunk to a two inch somewhere between the sewer line and the house and make it a full 3" line. It would probably be pretty cost prohibitive to do since I would be modifying a sewer connection.

I already have the permits for it. Just need to finalize the exact plans. thanks!

I'm thinking to avoid the issue with the power panel it may be best to cut into the basement floor concrete and run the drain through there. I will just need to verify that the drain connection is low enough that I can achieve proper slope for this.

Sounds like you have a handle on the situation.

Hopefully haha