New toilet install

[George R]

I would like to install a new toilet and sink in an existing 1st floor (large) closet with a full basement underneath (good access). I have a straight 30 ft run (3 in PVC) to an existing horizontal 3 in waste line from a 1st floor toilet. Vents are no problem, straight up to the attic from the existing closet.

The problem is, the best "fall" I can get on this 30 ft run is about 2 1/4 inches. I know it should be about 1/4 inch/ft., but is this 2 1/4 inch in 30 ft acceptable? There is no inspection, but I obviously want it to work properly.

I have a plan B, but it would be much more work.

Thanks in advance for any assistance.

 

[Mchiarit]

It is my understanding that the .25" per foot requirement is for drain pipes less than 3". Since you are using a 3" pipe, it may be more or less stringent. In any case, whatever the code requirement is, I recommend you follow it even if no inspection takes place. In addition to having drain problems, you could be the target of a lawsuit by a future owner.

 

[Sponsor]

 

[Prashster]

I've heard that the optimum slope is 1/4", but 1/8" is acceptable. However, for 30 feet, that'd still require 3 3/4" drop. 2 1/2" seems too shallow. If it were me, I'd go with plan B.

Is it possible to drop the main branch you're tapping into an inch or 2 to give you the proper fall? That would be quite simple, bkz you could re-use all of the existing drain. You'd just have to add a 2" coupler on the nearest vertical piece of the main drain upstream from where you're tapping in, and cut-out and reduce the height of the nearest vertical xition on the main branch downstream from your tap. Two cuts.

 

[Terry]

A three inch line is 1/4" per foot.

Is an inspector allows it, a 4" line can be run at 1/8" per foot.
Toilets need at least a 3" line.

 

[George R]

Thanks for the responses guys. I have to stick with 3 in. because the main stack is 3 in. copper. Plan B was to cut into the vertical stack, but it is in between two walls, one of which is an acrylic shower surround and the other is the finished wall of the steps to the basement. Very difficult access. But I guess I'll do what I have to do. Thanks again.