Transitioning from Slab on Grade Elevation to Sewer Line Elevation Outside

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Adam Doyle

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I building a one bed on bath unit in my backyard and connecting the sewer line from the unit back to my house. I had an inspector(young guy, pretty new at his job) come by today and fail me for the ~12" drop from the plumbing elevation under the slab on grade to transition to the elevation of the sewer line just outside the footprint of the building. He said that the 21.5 degree fitting at the bottom of the drop was going to cause clog issues, but I'm skeptical that a minimal transition would actually cause any problems. His solution was to cut the double 21.5 degree drop out and have a continuous steeper pipe coming down from the 45 degree turn in the slab all the way down to the reducer (3" to 4"). I mentioned that doing that would create greater than a 1/2" per slope and that the particles would be left behind. I don't feel like his solution is any better than what I already have installed.
Does my dual 21.5 degree drop seem acceptable for code? ( Im located in Utah)
Should I just leave as is and have a different inspector come out to see if they say the same thing?

Any help is appreciated!
 

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Reach4

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What is the slope on the 3-inch pvc downstream of the lower 22.5 -- at least 1/4 inch per foot? If so, new inspector if you understood correctly-- that the only objection was to having a 22.5 bend. I am not a plumber.

Do you have an outside cleanout for that line? That you want.
 

hj

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There is no such thing as "too much slope", and two 1/16 bends so NOT create an obstruction to the flow, so EITHER way would be correct, assuming the inspector was not a "90 day wonder" and NOT a plumber. (Three munce ago I culdn't spell inspector, and now I are one.)
 

Adam Doyle

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What is the slope on the 3-inch pvc downstream of the lower 22.5 -- at least 1/4 inch per foot? If so, new inspector if you understood correctly-- that the only objection was to having a 22.5 bend. I am not a plumber.

Do you have an outside cleanout for that line? That you want.

The 3" line has 1/4"/ft along the entire length except for the one section between the two 1/16th bends. I do have a cleanout located at the other side of the building ( highest and furthest point in the drain system) as well as two more cleanouts along the 65ft run of sewer line to the house.
 

Adam Doyle

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There is no such thing as "too much slope", and two 1/16 bends so NOT create an obstruction to the flow, so EITHER way would be correct, assuming the inspector was not a "90 day wonder" and NOT a plumber. (Three munce ago I culdn't spell inspector, and now I are one.)
Thanks for the info! He did mention a few times he doesn't know much about plumbing and that plumbers would know "how to fix it" if I just asked them. Doesn't inspire me with much confidence that he knows how drains are supposed to work...
 

Reach4

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Thanks for the info! He did mention a few times he doesn't know much about plumbing and that plumbers would know "how to fix it" if I just asked them. Doesn't inspire me with much confidence that he knows how drains are supposed to work...
It sounds to me as if you just quote some relevant code references that he may come around. Or you ask him what code he thinks you violate.

Maybe showing him this thread could help.
 

Jeff H Young

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Just kind of a nit picker. I don't like making people rework. but its not exactly top notch either.
I guess a challenge with the digging , I don't see a reason you plumbed it like you did, but I might throw a fitting on rather than do extra hand digging but its a little lazy.
the 4 inch main should have a minimum 3.5 inch cleanout in my code before dropping to 3 inch so that's an issue too i guess he didn't call you on.
agree the minor offset isn't major ,but why would you want that?
I knew an inspector that had our company that I worked for replace sections of gas piping that had couplings in it (I think there were a lot of couplings ) he said it was general poor workmanship . the piping was prefabricated and was reworked with too many couplings
 

Adam Doyle

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Just kind of a nit picker. I dont like making people rework. but its not exactly top notch either.
I guess a challewnge with the digging , I dont see a reason you plumbed it like you did, but I might throw a fitting on rather than do extra hand digging but its a little lazy.
the 4 inch main should have a minimum 3.5 inch cleanout in my code befor dropping to 3 inch so thats an issue too i guess he didnt call you on.
agree the minor offset isnt major ,but why would you want that?
I knew an inspector that had our company that I worked for replace sections of gas piping that had couplings in it (Ithink there were a lot of couplings ) he said it was general poor workmanship . the piping was prefabricated and was reworked with too manycouplings
My intent was to keep all of the 3" pipe (everything in the slab) at 1/4"/ft then using the 1/16th fittings to drop down to sewer elevation over a short distance instead of an 8ft run of 3" pipe dropping 12", thus giving it a 1.5"/ft slope. The reducer you see is actually acting as an increaser ( 3" piping in the slab increases to my 4" sewer line) and there is a 4" cleanout just outside of the picture.
Would it be better to have a true vertical drop where the two 1/16 fittings are?
 

Reach4

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His solution was to cut the double 21.5 degree drop out and have a continuous steeper pipe coming down from the 45 degree turn in the slab all the way down to the reducer (3" to 4").
I think you are saying that no 4 inch pipe is shown in your photos, and that feeds into 4 inch downstream of the photos, right?
 
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