Any idea why this was plumbed this way? Seems wasteful...

[jburt09]

Replacing a 4" cast iron drain that services a toilet, washer, and sink that's ~20' in length before it ties into a 4" PVC DWV line. There's another 2" cast iron drain for the kitchen and dishwasher that runs above it, crosses over and away from it, then connects with a 2" PVC 45 degree elbow that cuts back towards the 4" PVC. It's a lot of extra material and is in the way of where the new 4" PVC drain line needs to run (ideally).

Why would it have been plumbed this way? Is there any reason I wouldn't cut it out and just tie it in to the new 4" PVC right where it crosses over currently?

Thank you in advance for the time and input.

 

[Tuttles Revenge]

I don't spend a lot of time trying to figure out the why they did it.. unless its a pump line, then it can all be cut and simplified when you bring in the new PVC.

 

[Sponsor]

 

[Jeff H Young]

I think there is a reason I cant tell you what that reason is maybe something changed like a new septic coming out another side of house or went to sewer.
They ran the main and forgot the branch didnt want to cut it in middle just grasping but..... At a certain point lets ask this does it make sence to leave it ? or go with your plan?
Based on what youve said Id lean toward tie in in closer to the new pvc

 

[John Gayewski]

Draw a diagram of what your proposing to do.

 

[jburt09]

I don't spend a lot of time trying to figure out the why they did it.. unless its a pump line, then it can all be cut and simplified when you bring in the new PVC.

No pumps here! Just a mid 60s construction Florida home partially build on slab and the rest on crawlspace!

I think there is a reason I cant tell you what that reason is maybe something changed like a new septic coming out another side of house or went to sewer.
They ran the main and forgot the branch didnt want to cut it in middle just grasping but..... At a certain point lets ask this does it make sence to leave it ? or go with your plan?
Based on what youve said Id lean toward tie in in closer to the new pvc

Completely speculating but I think what may have happened was they didn't have a CI wye and/or didn't want to cut it into a smaller piece with two no-hub ends...

I think I'm going to tie in with a 4x4x2 wye and get rid of more of that old cast iron!

Draw a diagram of what your proposing to do.

Sure thing! Did my best and while it may look ridiculous, it's pretttttty close to what's actually there.

 

[Jeff H Young]

Yea I think what you plan sounds good run it in pvc

 

[Reach4]

Assume W is the washing machine standpipe. You want the lavatory drain to connect to the toilet drain before the standpipe drainage joins in.

I cannot really follow your diagram. I don't know where the toilet is.

 

[jburt09]

Yea I think what you plan sounds good run it in pvc

Will do! Going full send!

Assume W is the washing machine standpipe. You want the lavatory drain to connect to the toilet drain before the standpipe drainage joins in.

I cannot really follow your diagram. I don't know where the toilet is.

W is washing machine - correct. As for the 'lavatory drain to connect to the toilet drain before the standpipe'...do you mean in relation to the septic tank as a final destination? In that case...the toilet drains into the drain line before the water from the washer standpipe stack. Where the washer connects to the vent is above where the line continues down to vent the lav if that makes sense.

I edited this in hopes it clarifies. The circles are vent stacks...

 

[Jeff H Young]

sounds like the scope of work is changing ? you want to change a straight length of 4 inch to pvc and put a 4x2 wye in close to K/S right but whats all this other stuff got t to do with it, are you gutting the walls and replacing the entire dwv system?

 

[jburt09]

sounds like the scope of work is changing ? you want to change a straight length of 4 inch to pvc and put a 4x2 wye in close to K/S right but whats all this other stuff got t to do with it, are you gutting the walls and replacing the entire dwv system?

Hey Jeff - hasn't changed. Apologies for the confusion the image may have induced. I only included to show how it ties in to the rest of the home and then out to septic. The only piece that was called to replace is the 4" CI DWV (circled in red in the first pic). The only change to the original scope of work is cutting out the 2" kitchen sink drain line and tying it in right where it crosses the 4" DWV line (circled in blue in the second pic).

 

[Jeff H Young]

Got it !