Are 2 Quarter (90) Bends Allowed In Horizontal Drain Line?

[herynkc]

Im doing some renovations in my basement. I am in the process of both relocating my washing machine / sink drain line and digging a hole to pour a spread footing for a column which I am moving. The footprint of this footing interferes with my current drain line path, therefore I have redesigned the drain line (as pictured in my drawing). The photo shows the current layout of the drain line. It looks like they have incorrectly installed a sanitary tee in place of a wye or combo wye. So is it a bad idea to have those 2 90bends back to back? I dont want to have a cleanout between them, nor do I think that there is room to do 2 45 bends since my furnace is on the other side of my proposed drain line to washing machine and sink. Thanks for your help

I have drawn on the photo in green to layout my proposed redesign, black lines show uncovered existing lines, red is the square area I cannot be below.

 

[hj]

A double Y would be a better fitting, and, while you SAY it is 3", the photo seems to imply it is only 2" piping.

 

[Sponsor]

 

[herynkc]

The sanitary tee is actually 4" reduced down to 3" lines everywhere else.

So im eliminating the straight run coming off of the current sanitary tee, so do you mean a wye and a 45 bend? A double wye gives me 3 offshoots, I only need 2.

 

[Terry]

I would like to see a wye further back for the toilet, and then a 45.

 

[herynkc]

Thanks for all your feedback. Im going to go with a wye and a 45.

Upon excavating the rest of the area, Ive found a large void beneath the slab. Is this common in older homes? Any plumbers seen this?

 

[hj]

You plug the third center opening. OR move the Y down and use a street 45 in the end of it.

 

[Jadnashua]

Got critters in there? When pouring a slab originally, that area had to be filled in, or the concrete would have filled it in.

 

[herynkc]

I ended up installing it like this, a wye with a 45 and a 22.5 on the end: