Too many bends in 3" sewer pipe?

[Daveem]

Hello! We are having an issue with the sewer line serving our master bath becoming clogged. Our house was completed last year, and since then, we've had to snake the 3" PVC line several times.

The clog always occurs at the point where it makes a perpendicular turn, right in the area of the 45 ell and the 90 (see photo). The clog always consists of solid waste only, as we've tried not even flushing TP down the toilet, but it clogs nonetheless.

I was wondering if it would help to move the cleanout over to between the next two floor joists to the left, then a short section of 3", then a 45, another straight section, and another 45 to the stretch on the perpendicular wall. I thought maybe this would allow for better flow than the 45/90 combination. Any thoughts?

 

[Daveem]

An update...after posting my original message, I got to poking around the forums, and noticed many references in various threads addressing the correct slope of a drain line (1/4" per foot). It dawned on me that the stretch of line we're having problems with didn't have much slope, so I went downstairs to take some measurements.

I found that the roughly 22 foot long line leading up to the 45 and 90 I mentioned in my original post, there was a drop of only about 2", when (if my calculations are correct), that stretch should drop about 5 1/2" -- quite a difference from the 2" actually present!

I've attached a photo of the line in question -- it runs along a steel beam, and only drops about 2" from the cleanout in the foreground to the point where it reaches that wall in the background, where it makes a bend and continues along the wall.

So, I'm guessing that adding the correct drop to the first section is the solution.

 

[Sponsor]

 

[Terry]

You need the 1/4" per foot drop. That sounds like the issue. It's not the fittings there or the cleanout.

 

[Daveem]

You need the 1/4" per foot drop. That sounds like the issue. It's not the fittings there or the cleanout.

Thanks, Terry....have left a message with the plumbing firm which did the installation. I think that maybe they can drop that length without much of an issue, and the end of the dropped section looks like it might line up in the vicinity of the end of the next, perpendicular section of pipe (beyond the existing 90)...looks like plenty of slope beyond that.

By the way, a great big THANKS for operating this forum for everyone!

 

[Reach4]

Any opinions on the plumber making the pipe slope the full drop, maybe 1/2 inch per foot? Replace the 90 and 45 with a long sweep 90?

 

[Sylvan]

Shame today's "techs" never learned to carry a ruler and level .

Be thankful the entire line was not back pitched .

I wonder what training the inspector has

Will the installer do the right thing and refund all the money wasted on having this line snakked out?

 

[Daveem]

Shame today's "techs" never learned to carry a ruler and level .

Be thankful the entire line was not back pitched .

I wonder what training the inspector has

Will the installer do the right thing and refund all the money wasted on having this line snakked out?

I snaked the line out myself (did buy a nice, long, heavy duty snake for the job). Since it is the weekend, I left a text message on the company's website, informing them of my findings, and advising them that I will be calling them during the week. Will see what they say!

 

[Master Plumber Mark]

From the pictures I saw it looks like you could un hook the last 3 or 4
J hooks on the line at the end and lower that line yourself fairly easily......

 

[Jadnashua]

The spec calls for a minimum of 1/4"/foot...more is okay as long as the fixtures are all properly vented. Consider that it works with a vertical line...LOTS more than 1/4"/foot.

 

[Daveem]

From the pictures I saw it looks like you could un hook the last 3 or 4
J hooks on the line at the end and lower that line yourself fairly easily......

I'm not sure...there is a drop of less than 2 inches the whole 22+ foot section starting at that cleanout, down to that intersecting wall. And now that I've looked more closely, I'm not sure that, even if the end of the first pipe were dropped an additional 3 1/2" to meet the 1/4" per foot drop required, it would end up above the end of the pipe perpendicular to it along that wall (after the ell removed and the 90 realigned). Will take another look at it tomorrow.

 

[Master Plumber Mark]

it does appear to have some good fall on the back wall and I dont see any hangers holding anything...
if you are lucky sometimes all it takes is to start at the beginning of the whole run and either lower the
hangers as much as possible or simply go out and buy some strapping and lower it as much as possible and
re-hang the whole affair..... a roll of strapping is dirt cheap and so are nails.
New J-hooks dont cost much either.......

 

[Sylvan]

"simply go out and buy some strapping and lower it as much as possible and
re-hang the whole affair..... a roll of strapping is dirt cheap and so are nails."

To think all these decades I use clevis hangers Steel J hooks and riser clamps when I could have used band iron and tell the inspectors I saw a LMP suggest this on some site so it must be some code approved I am sure they would say OUTSTANDING job

 

[Master Plumber Mark]

Well, you know that is because you do mostly commercial work and I
do home plumbing service work where "holy iron" is used most often....
Its cheap, fast, and will last forever.......

What you would use on a commercial
applications would be over-doing it in a common basement....