Attn. Plumbers Residential home question

[Pixguy]

Ok, a gc is building a home for us and the waste pipe has been run in a full basement and there is an area where the master bath line is dropped at a 45° to drop below the main duct that runs along the support beams. The drop is approx. 30 and then takes a 90° turn.

My question is coming from a layman who always thought that the waste pipe should always drop 1/4 per ft and that a fast drop like that will allow the liquids to run past the solids and I will eventually have a buildup at that 90.
Behind that area is the toilet of course, dbl. sink, shower(used twice daily) and a tub(used approx. once a week)

I will provide a picture today if I get to the site. Am I worried needlessly? Will the additional liquids from the shower wash down anything left behind? I would ask the gc or plumber but they would likely just cya and tell me itç—´ fine and I want to take care of this before we close.

 

[gary49]

Two 45's to offset under duct and then a horizontal 90 degree turn? Fine if 90 is a long sweep fitting. Or is it a 90 from horizontal to vertical? Which would also be fine. Problem with liquid outrunning solids is generally when slope exceeds 1" or so per foot of run, but is less than a 45 downslope. Also usually occurs on long downslope runs--think running down a hill outside the house. You have no worries on this one.

 

[3Ts]

+1 I've got a 45* drop for 3' to 4' in my main 4" sewer line then goes back to the normal slope. It's been 6 years now and no problems with it.

 

[mike48130]

I doubt you will ever have an issue. With the constant use of water, it will push anything thru. Especially PVC. it doesn't rust or corrode list cast and cause friction. I have a toilet at my dad's house that they put the Y in backwards, and it flows in upstream. Been like that for 80 years now. No issues. Only found it when I had to break into a ceiling to fix some water lines. Just laughed and said WTF.

A lot of older houses (and new in some areas) have U-traps on the main line. That always seemed like a bad idea to me, but it works as long as you have constant water usage.

 

[EddieWalker]

With PVC pipe, it's pretty much impossible to have any issues with solids building up in a pipe. All of those issues where back when cast iron was used, and everything got stuck in that pipe!!!

 

[Captain Dirty]

. . .My question is coming from a layman who always thought that the waste pipe should always drop 1/4 per ft and that a fast drop like that will allow the liquids to run past the solids and I will eventually have a buildup at that 90.
Behind that area is the toilet of course, dbl. sink, shower(used twice daily) and a tub(used approx. once a week)

In the world of drains anything between vertical and 45ｰ is considered vertical. As far as the 90 which I take to be at the junction of two 45ｰ (an hence vertical) runs, it should be less of a choke point than 90's going from vertical to horizontal, e.g. the closet bend under the toilet.

 

[RNeumann]

You interviewed and researched contractors before you hired them. Now is the time to trust the folks you hired. The plumbing is fine. Their is the ideal world and reality. Reality is HVAC and plumbing are always at odds. It sounds like your HVAC and Plumbing contractors did a fine job getting everything run......let go of their ears. I’m sure the job will go well. You will end up with a nice home. Enjoy this exciting time!!

 

[buckeyefarmer]

Trying to understand the problem. My 2nd floor drains drop 8' to the basement ceiling, crosses the room, then drop another 10' to go under my footer. Not sure how a short drop to go under ductwork would hurt it.

 

[Pixguy]

I have no problem letting it go if you guys tell me it’s fine. I haven’t said anything to them.

Here’s the area I questioned.

 

[EddieWalker]

Where is the purple primer?