Waster discharge pipe size ? - Plumbers say tear up my new slab to up size risers

[vpracer]

So building a brand new home, framing is up, some electric done, single story, slab is about 110ft long, has 4 toilets, 3 and 1/2 bathes. Currently I have a 4" main line waste discharge pipe with 3" risers to the toilets. My builder just fired the old plumber who did all that install and the new plumber wants to jackhammer my brand new slab and install 4" risers. I'm not drinking the Koolaid on this. Seems extreme however I don't want to be plunging my pots every time you flush. Its a long run to the septic tanks. My question is would you guys live with 3" or do this demo for the 4" riser?

 

[TemporaryKubotaOwnerMark]

You want to do it now, or later when the incessant clogs prove your builder was right?

Any plumber who would use 3" for toilets should be forced to swim in a cesspool.

 

[zmountaineer]

We went with 3" and the logic (whether it's BS or not) was due to the low flow toilets. And it being easier to send solids through with less water.

 

[oosik]

I have a 4" main line running the entire 60' length of the house with a 3" riser on each end of the run. Worked fine for 35+ years. If you have a 3" riser to each toilet - that's more than adequate.

 

[Billrog]

I've never seen a 3" riser plugged yet if it will go threw the neck in a toilet it will sure go threw a 3' pipe. Sounds like the new plumber is just trying to impress some body.

 

[vpracer]

I sure thought 3" would be ok. Seems like alot of opinions on it and more importantly the thought of demo'ing a brand new slab makes me sick to think about. Would it matter if I used the higher gpm flushing toilets vs. those low flow ones?

 

[buckeyefarmer]

No problems in 20 yrs with my 3" pipes.

 

[kenmac]

I use to plumb residental with 3'' Your S trap will clog B-4 the 3'' risers will

 

[RobertBrown]

Based on my knowledge of turds....dimensionally. I would not spend the money to upsize at this point in time. My experience goes back quite a few years, however it is limited.
I suppose you could say my opinion about **** is worth ****. But....after all, we are talking about ****.

Hope this helps

 

[KYErik]

3" for the risers should be fine. I've never heard of a 3" pipe that serves just a toilet plugging. I built and plumbed a 2 bathroom house with 3" pipes to each toilet- that part passed the plumbing inspection just fine and 14 years without any problems...

Maybe the new plumber is wanting to buy a boat and needs to make a down payment

Seriously, just ask your local inspector if 4" is required.