# Lowering kitchen drain pipe - PVC



## plumbdoc (Dec 24, 2009)

*use an 1 1/2 abs glue type trap*

Use a 1 1/2 abs or pvc glue type trap. when you use one of these traps you can add a pvc 1 1/2 union to the short bend 90 and add a piece of pipe to the trap to lower it. No it does not pass code but it will work without tearing the wall or cabinet out. picture the pipe coming out the wall with the trap 90 facing down. glue a pvc union on the trap 90 so the pipe is going towards the ground. now glue on your trap. you have just lowered the trap by a few inches. its kind of hard to explain they dont make a fix for it on the shelves. so you have to think and make one that will work. this will fix your problem and not leak as long as you do it just like i said. Hope this helps.


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## LeviDIY (Apr 16, 2009)

plumbdoc - thanks for the reply.. I'm concerned about drainage within the disposal, and have thought about jury-rigging something like you've written up, but really am looking for advice on the feasibility of lowering the drain pipe, given limited DIY-manship.


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## plumbdoc (Dec 24, 2009)

It sounds to me like the feasibility is a pain in the A**. didnt you say you would have to cut hole in the back of the cabinet and then sheetrock to get to drain pipe. What i suggested would work fine. No leak and should drain fine from disposal. But if you want to lower drain pipe that would be the best bet! I just hope the plumber didnt put in a dirty arm (ran the drain horizontal in the wall before stubbing out) or you might be wasting your time cutting into the wall.

Also you might want to call a plumber and have him take a look and see if he can rearrange the plumbing under the sink to make it work. Is there two drains in the sink or just the one for the disposal?


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## LeviDIY (Apr 16, 2009)

thanks again... working with single sink set up here.. I may "temporarily" (read: not looking forward to a plumber's bill anytime soon) try PVC glue... but never used it, only those nuts on the Home Depot-sold pieces... any advice for a PVC gluer first timer?


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## rjniles (Feb 5, 2007)

Cut out the back of the cabinet, a piece about 6" wide and 12 " tall should do it. Open up the drywall and lower the trap arm. Use a Fernco connector for the upper end of the vent line. Don't worry about the hole in the drywall as no one will ever see it. Cut a patch of Luan plywood about an inch bigger in each direction that the hole. Cut a hole in the Luan for the trap arm and screw in place over the hole you cut. Stain to match cabinet if you are fussy.


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## LeviDIY (Apr 16, 2009)

see its the actual lowering of the trap arm and vent line... I am wondering how that is specifically done.


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## rjniles (Feb 5, 2007)

LeviDIY said:


> see its the actual lowering of the trap arm and vent line... I am wondering how that is specifically done.


In the wall you will find a tee, drain going down, vent going up, trap arm coming out of wall. Use a sawzall (or what you have) to cut the tee off top and bottom. Cement a new tee on the drain (pipe going down) (this will lower the trap arm about1.5"- If you need more cut some more off the drain pipe), cement a short piece of PVC going up and connect with Fernco connector. Bring a stub oit of wall for new trap arm. Install you cabinet patch. Holding the P trap in place determine where to cut off the trap arm stub. Install a trap adapter on the trap arm and connect the P trap.

Once the wall is open it will take as long to did it as it did for me to type this. I am a slow typist

BTW, a previous poster mentioned a dirty arm. This is a pipe that goes right or left after it goes into the wall. The reference means that it is both a drain and a vent It is also called a wet vent. . This is sometimes done to avoid a window directly above the sink. If you find this check back with the group on how to proceed. It is more work but it is doable.


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## plumber Jim (Mar 30, 2008)

Before you cut that wall open post a picture of the underside of your sink. the tee may not be in the wall right behind your sink unless you remember seeing it right there before you drywalled. Some go horizontal then run to the tee on the left or right. Post a picture and we can see if you have any other options.


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## Alan (Apr 12, 2006)

plumber Jim said:


> Before you cut that wall open post a picture of the underside of your sink. the tee may not be in the wall right behind your sink unless you remember seeing it right there before you drywalled. Some go horizontal then run to the tee on the left or right. Post a picture and we can see if you have any other options.


x2 on this.

I wouldn't hesitate if it was just drywall, but since there' s a cabinet back involved i'd post a picture.


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## oh'mike (Sep 18, 2009)

Levi---This happens all to often!

The advice you have been given is right on the money--Open the cabinet and drywall--

You will see what parts you will need as soon as it's open.

Once the new tee is installed--and the cabinet back is patched--

Loosely install the two P-traps and figure out the neatest arrangement of T's or Y's or whatever will give you the most room under the cabinet.

If you had a single P-trap set up before now is the time to do it right,One P-trap per drain is code here----May not be where you are --but it will give you a more trouble free drain system.

---Mike--


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## LeviDIY (Apr 16, 2009)

I'll get ya'll a picture tonight when home from work... thanks!!


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## LeviDIY (Apr 16, 2009)

*Pictures*

Here are a couple pictures... not the greatest detail, but let me know if you need more, or a different view/angle. The black elbow is coming out of the disposal and remember, the P trap right now is reversed going into that and then the drain coming horizontal from the wall..















It appears that the exit from the disposal is now essentially even with the drain pipe heading into the wall... ideally that should have a downward slope to it, correct? Would this lead to slow drainage?


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## oh'mike (Sep 18, 2009)

Levi--Good enough pictures--Is that a single sink set up?

Before you start cutting---loosely install the p-trap correctly so you know the minimum distance that the T must be lowered.

The pipe may be 2" going down--and 1 1/2 going up to the vent.

T's are available with 2--1 1/2--1 1/2 openings --That's why I suggested you open it up first--
then go shopping.

The garbage disposer can easily be loosened and turned or removed---There is a silver collar where the machine meets the sink---it has three rings on it --just the size to stick a heavy phillips screw drive into.

Slip a screw driver into a ring and give it a pull--1/4 turn and the machine is loose.


---Mike--Good luck--Have fun--


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## Alan (Apr 12, 2006)

We rough in kitchen sink drains at 16" from the floor. This should give you plenty of room, although double check first in case for some odd reason you have a super low countertop and extra deep sink.


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## velvet (Jul 6, 2010)

Had to register just to post on this thread and thank you all for contributing to it. I have a similar situation, except my height difference is about 4" between choosing an undermount sink and putting the disposal on the deeper bowl.

Without this thread I might still be trying to fashion a pipe contraption that would reach the in-wall drain. I've "seen the light" now and have called for a more professional opinion to come in and take a look at my situation


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## SillyGod (Mar 25, 2016)

I'm wondering what ended up being the solution to this one? My photo looks almost identical!


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## kenju4u (Aug 15, 2016)

Hi,

I am in the exact same boat right now. I had granite countertops installed which came with a 9" sink. My current setup which was a 5 - 6" sink with a garbage disposal was a perfect setup since the past 8 years. Now The sink is too low and even without a disposal my drain pipe is sitting just below the dishwasher inlet under the sink flange. 

I was quoted $585 to lower the drain pipe without the patch job on the wall. I find that way too expensive since I can see the T joint and I don't believe its that much work. 

do you guys have any advice on what I should do? My current setup just barely works without a garbage disposal but I want to make sure the work is done right the first time. 

some reason my images are showing side ways. Not sure how to correct that.

Current Setup:









Previous setup:







Ken


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## miamicuse (Nov 13, 2011)

If you are really just one inch off, then before you tear up the wall and cabinet, I would look for a different disposer. I remember seeing different brands of disposers with some variations on the vertical position of the outlet. Some are made shallower than others.


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## oh'mike (Sep 18, 2009)

I've done dozens of those ---what do you want to know----??

Open the cabinet back and drywall---an osculating multi tool is the best for that part.

If the drain goes down from the T--the job is rather routine--if it runs horizontally --
You might be in for a long day.

As an experienced pro, I can get one done in 1 1/2 to 2 hours.


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## kenju4u (Aug 15, 2016)

@miamicuse - It would not be only 1 inch off if i put in a disposal with the current setup. Its 1 inch high without the garbage disposal as shown in my current setup picture. 

@oh'mike - The drain does go down from the T but it looks likes there is a bend at the bottom which is going to the back of the wall. My bathroom is right behind the wall so I am sure that drain connects to the shower drain. Anyways I should still be ok to move the T bend since I am not going to be going that far down. 

I am also trying to find out if I can get a shallower sink 5 1/2" instead 9" which would resolve my issues without doing surgery behind the wall. 

I am attaching some pictures of what the behind the wall looks like for references.

Pictures are side ways. down is to the right.


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## miamicuse (Nov 13, 2011)

You are going to have to open up the sheet rock more, wider and lower to lower the drain.

The two copper supply lines that run horizontally is going to be in the way as you install your new fitting. In a PVC installation like that I would prefer to use a repair coupling and solvent weld everything but the copper supply lines would make this a real challenge so my suggestion would be to use two banded Fernco or mission couplings. Like this.









They come in variety of sizes and for different transitions of sizes and materials. You need one at the bottom (2"PL X 2"PL) and one on top (1.5"PL X 1.5"PL).

Your existing installation is a sanitary tee with a 2" bottom for the drain and a 2X1.5 bushing to reduce to a 1.5" vent.

The basic idea is to put together a new assembly, consisting of - from top - a 1.5" fernco coupling, connected to a short piece of pipe, which connects to a 1.5X2 bushing, which is connected to the top of a 2" sanitary tee (street), connected to a second 2" fernco coupling.

Your shopping list:

1.5" PL X 1.5" PL fernco banded coupling
short piece of 1.5" SCH 40 PVC pipe
1.5"X2" PVC bushing
2" street sanitary tee (make sure it's street with the spigot end at the bottom)
2" PL X 2" PL fernco banded coupling
another 1.5"X2" PVC bushing for the 2" branch coming out of the wall
PVC trap adapter with street connection to insert into the branch
PVC primer and cement
torque wrench to 60#

Before you cut anything on the existing I would first assemble the new assembly.

Take the street sanitary tee, solvent weld the piece of bushing to the top, then a short piece of 1.5" pipe. say 6" long into that.

Then take the 1.5" banded coupling, remove the metal band, insert the top end of the 1.5" into that, it can only go in half way and bottom at the stop in the middle. Now that the other end of the rubber sleeve and fold it back inside, like how you would fold back the top of a tube sock...as much as you can to the half way point. Do the same with the 2" sleeve onto the street end of the san tee. This will be your new assembly.

Position your new assembly with the san tee at the correct vertical position. That will give you the exact spots you need to make your cut into your existing PVC line and how much more sheet rock you need to open up for the proper cut.

Once you have made your cut you should have a "gap" in your line the same length as the new assembly. Put the two metal sleeves onto the existing pipe, and get them out of the way (using tape or whatever), insert your new piece into place, unfold the sleeves onto the existing PVC pipes, slide the metal bands over the sleeves and torque to 60#.

I would solvent weld a 2X1.5 bushing into the 2" branch then a street trap adapter.

Alternatively, you might be able to find a PVC 2X1.5X1.5 PVC street sanitary tee at a plumbing supply store and that makes those bushings unnecessary.


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## Javiles (Dec 12, 2011)

kenju4u said:


> Hi,
> 
> I am in the exact same boat right now. I had granite countertops installed which came with a 9" sink. My current setup which was a 5 - 6" sink with a garbage disposal was a perfect setup since the past 8 years. Now The sink is too low and even without a disposal my drain pipe is sitting just below the dishwasher inlet under the sink flange.
> 
> ...


A homeowner called a plumber, which was having some kind of leak in his plumbing. Owner asked the plumber if he could help identify and fix the problem. plumber walked up to a wall and made a small hole found the leak and fixed it, the homeowner was thrilled, and told the plumber to send an invoice. 

The bill arrived, for $1,000. Homeowner was shocked it only took you 30 minutes and asked for a breakdown. plumber sent another invoice, indicating a $100.00 charge for making the repair and $900 for knowing where to find it.


What is the value of a plumbing job? performing the actual labor can easily be the smallest part of the process, with the real value lying in correctly diagnosing the problem and coming up with a viable solution to it.


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