Check out some similar questions!

whburgess · Apr 17, 2010, 04:17 PM

Hi. I am not a plumber and but am doing my own plumbing in my addition to my house. I have some concerns and you guys were really good with earlier question from a few days ago. I appreciate your help.

I've included an image/drawing below of my plumbing drains for my addition to my house and how it is tying into my existing plumbing. The existing drains are in black on the drawing. The new lines are in red. I am to the point of the 90 degree elbow fitting labeled 90a. That elevation is fixed. My questions are about getting from that fitting to my existing sewage lines. Here is some info about that.

1. From point 90a to wye c is 9 feet.
2. from point 90a to wyc c is a 8 1/2 inch elevation drop.
3. you can see that I have to drop down before I get to wye c one extra time because there is an obstruction (copper water line) in the way.

Here is my concerns--
A. Are there too many 90 degree elbows in this new line from my toilet to the existing sewer line? Do I have to worry about one of them getting stopped up?
B. I am having to use two 45 elbows for the drop down because two 90's would be more then the 8 1/2 drop I need. I don't know what a drop for two 45's will be. Will I still be able to get proper grade for this 9 feet if I have the two 45 in there for a drop down?
C. Or should I forget dropping down with the two 45 elbows.. and just do a straight graded run from 90a to wye c? The obstruction would not be an issue in this case by the time the graded line gets to where it is, it would be under it. The reason I am asking if this would work is because I have been told that grading too much in a line will cause liquids to outdrain solids and solids could get hung up. This would be almost an inch per foot grade.

Any other comments? Thanks so much.

Milo Dolezal · Apr 17, 2010, 05:22 PM

If you use proper fittings for each transition than you should not worry about whether you have too many 90's. Combine "Y" and Street 45 to make 90 degree horizontal turns. In my area of operation, we are required to install clean out after each 135 degrees of turns. Overall, run your drains in straight lines as much as possible. The more turns you have - the more potential problems you are creating.

whburgess · Apr 17, 2010, 06:01 PM

Hi Milo. Thanks for that information. I will definitely use the y and 45 instead of a 90 for the horizontal turn. In your opinion would it be better to use the two 45's to drop down to clear the obstruction... or would it be better to leave out the fittings and grade that 9 feet of run an inch per foot in order to clear the obstruction?

Milo Dolezal · Apr 17, 2010, 06:15 PM

Grade it. Less fittings you use - better for you. If you ever need to use 3/4" snake it will negotiate turns in your sewer line w/o problem.

Every time we are roughing-in new waste lines we try to go with the main run as straight as possible. Then we branch off to each toilet and /or group of fixtures. So it looks like a tree. Also, every branch has to start with toilet. In other words, no other fixture will connect to the sewer line behind toilet connection - but in front of it...

I work under UPC. Our code requires one clean-out for each 135 degrees of bends. However, we have other Experts here who work under various plumbing Codes and all across the country. Let's give them chance to respond as well...