New Basement Drains and Vents

[PatrickH]

Thanks for the site!

I have a few questions about installing a new 3/4 bath in my basement. I plan to add a new vanity, toilet and shower. The basement has an existing 1/2 bath rough in that I need to modify in order to move the toilet and install a shower. I've enclosed an existing JPEG and a new rough in JPEG, which shows the modifications. The existing rough in included a toilet outlet, and wet vent from the outside wall. There's a T installed for the sink trap that's been capped off. The vent goes up to the roof from the basement ceiling. I plan to install a 22.5 degree turn in the toilet drain to relocate, and install a Wye fitting to catch my shower. I plan to vent the shower from the same vent that feeds the sink on the other side of the bathroom. A few questions...

1. Does my install look correct?
2. The existing pipe is ABS, and so I plan to order the ABS pipe and fittings from the internet, given I can't find it in the big box stores. Why is that?
3. My existing toilet turn up has a 3" 90 reduced to a 4" drain pipe. Could this be a turning radius issue with a 4" ninety? Can I turn up a 4" 90 for the new install?

 

[PatrickH]

So am I completely messed up in my thinking for this?

 

[Sponsor]

 

[Plumber69]

So am I completely messed up in my thinking for this?

This looks right to me, most toilet flanges 90 right after the flange. Anything under slab is good to run 4" for your main, I would never run 1 1/2 under a slab. You havent just saying

 

[Terry]

That works for me. Maybe..........
One thing to consider is runing the lav line in 3" with a cleanout at the wall, or perhaps under the cabinet. The lav wet vents the toilet.
After the cleanout, you would continue with 2", with a 1.5" trap arm.

Since you are putting the lav on the other wall, that adds some bends, and removes it from the vent. You would need to vent within 42" of the trap, and no more than 135 degrees of change on it. Nobody is buying the 180.
If you slide the cabinet to the wall, and catch it from the side, that takes of some of that.

The shower looks fine too.

On cleanouts.
Inspectors like them at the end of the run.
If the cleanout isn't there, and the line needs snaking, the toilet gets pulled first.