tshannon
New Member
Hello,
I have made use of the professional advice goldmine on this forum many times in the past, but always by reading existing threads. With my latest plumbing project I figured it's time to post a thread of my own! I am firmly in the DIY class, and I would love advice from others out there (DIYers and professionals alike) so that I can learn more about proper plumbing techniques. Oh, and my city uses the 2019 California Plumbing Code (based on 2018 UPC). So, enough introduction, here's the project:
I am hoping to add a second bathroom to my house. The trouble is, my house is on a slab and all the existing DWV piping is under the finished floor or inside finished walls. While not entirely out of the cards, running what amounts to a second sewer lateral is something I would prefer to not have to do to get this bathroom built. Luckily, there is an accessible cleanout for the under-slab piping, and that's where I am hoping to hook up the waste network for my second bathroom. Due to the size of the cleanout (2") and it's elevation, I plan on using a macerating pump from Saniflo in this second bathroom. I know that macerating toilets don't always get a lot of love on this forum, but it seems like the best solution for my situation. I'm definitely open to hearing alternatives though I am also curious to hear feedback on this macerating solution. See the diagram below:
In case it's hard to read, I've uploaded the full-resolution schematic here.
There are probably other things I'm doing wrong, but the two key areas I've been worried about are:
Apologies for such a long post, but I figured a bit more detail is better than being vague. Thank you all for your fantastic advice over the years and for helping DIY'ers like me get more educated!!
I have made use of the professional advice goldmine on this forum many times in the past, but always by reading existing threads. With my latest plumbing project I figured it's time to post a thread of my own! I am firmly in the DIY class, and I would love advice from others out there (DIYers and professionals alike) so that I can learn more about proper plumbing techniques. Oh, and my city uses the 2019 California Plumbing Code (based on 2018 UPC). So, enough introduction, here's the project:
I am hoping to add a second bathroom to my house. The trouble is, my house is on a slab and all the existing DWV piping is under the finished floor or inside finished walls. While not entirely out of the cards, running what amounts to a second sewer lateral is something I would prefer to not have to do to get this bathroom built. Luckily, there is an accessible cleanout for the under-slab piping, and that's where I am hoping to hook up the waste network for my second bathroom. Due to the size of the cleanout (2") and it's elevation, I plan on using a macerating pump from Saniflo in this second bathroom. I know that macerating toilets don't always get a lot of love on this forum, but it seems like the best solution for my situation. I'm definitely open to hearing alternatives though I am also curious to hear feedback on this macerating solution. See the diagram below:
In case it's hard to read, I've uploaded the full-resolution schematic here.
There are probably other things I'm doing wrong, but the two key areas I've been worried about are:
1. With the macerating toilet discharging upstream of shower/bath 1, I might be putting myself at higher risk for sewage backing up into shower/bath 1. I think nearly any bathroom drainage system theoretically has the potential to back the toilet up into the shower given a large enough clog in just the right spot so I'm not sure if this is unique to my proposed plan or not. Perhaps it's just more likely in my planned layout.
2. With the existing bathroom, plus the laundry room and the proposed second bathroom all discharging into the same 2" branch line, I think I would be beyond the maximum number of fixture units for that 2" line. Here is how I figure it based on California Plumbing Code tables 702.1 and 702.2(2):
Is my proposed plan dead on arrival, or is there some way to make this work without tearing up the floor of my bonus room, garage, and driveway for another sewer lateral?2. With the existing bathroom, plus the laundry room and the proposed second bathroom all discharging into the same 2" branch line, I think I would be beyond the maximum number of fixture units for that 2" line. Here is how I figure it based on California Plumbing Code tables 702.1 and 702.2(2):
Laundry = (3.0 units clothes washer + 2.0 units) = 5.0 units
Existing bathroom = (1.0 units lav + 2.0 units shower/bath)= 3.0 units
Second bathroom = (4.0 units macerating pump @ 27 GPM) = 4.0 units
...For a grand total of 12.0 units on a 2" line. As far as I can tell, 8.0 units is the max allowed per CPC 703.2Existing bathroom = (1.0 units lav + 2.0 units shower/bath)= 3.0 units
Second bathroom = (4.0 units macerating pump @ 27 GPM) = 4.0 units
Apologies for such a long post, but I figured a bit more detail is better than being vague. Thank you all for your fantastic advice over the years and for helping DIY'ers like me get more educated!!