Waste drain way too high?

[JonathanB]

So here's the thing, suddenly under the sink there was a leak. This is not our house, it's my wives mother house. We moved in 6 years ago because she moved out and we needed a place. She bought it in 2002 and lived there several years.

Anyway, as long as we've been here there has always been slow draining of water and when the dishwasher runs water sometimes backed up into the sink. Wife never really complained about it, I guess because that's how it was when we moved in.

So I literally touched the pipes under the sink and one just snapped right off, just by poking it. It looks like it was an S trap, not a P trap. Anyway, the amount of corrosion was significant and rush. I removed all the plumbing from under the sink and was surprised to see the drain so high. It might even be higher than in the pictures. The sinks are not even deep sinks, about 8 inches. Now I tried to install a normal P trap and do it that way, but the damn sink WILL NOT drain properly. I've tried every combination with my limited knowledge and the water just settles in the sink.

Here is a picture. In fact, it might be higher than the picture. Not measured exactly, since it's an awkward tight fit, but it seems almost flush with the sink drain. Wife is mad at me and said, can I not just put it back the way it was. Well, the pipes were breaking apart from rust and corrosion and can't reuse them, and don't even remember the exact setup before, but it wasn't working right anyway.

I told my wife that we might have to cut into the wall and lower the drain, but here's the other problem. The wall behind is by the looks of it cement board, and I know it's going to be a messy, crappy job. My wives brother was telling her the drain is fine and it doesn't need to be moved. He works in a construction field so she is believing him over myself and telling me he said just put in some pipe and a P trap and it will be good to go. Well, I did that already, and it isn't good to go.

If you look at the picture, the sink drain and waste drain are almost level, maybe an inch difference from the top of waste drain. Possibly even less, 1/2 inch.

So am I right to say, the drain needs to be lowered? There's nothing I can do with this high drain/sink setup without water just sitting in there? I have a feeling that's what was happening before hence the really bad corrosion. I am surprised this was even given a "good to go" in 2002 when her mom moved in.

 

[JonathanB]

Here is a picture of the waste drain and the bottom of the sink.

 

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[Jadnashua]

The trap arm cannot have vertical rise to it...from the outlet of the trap (the trap arm), there must be approximately a 1/4"/foot downward slope to the point where it then turns down (which should also be the point where it is vented). You can't go down other than the normal slope prior to being vented.

It looks like that can't happen with what you have. Now, you may be able to find a shallower drain for your sink than what you have that might make it work.

The brass tubular stuff doesn't last as long if there's standing water, and if your water isn't hot enough, the dishwasher detergent can be corrosive to it. It generally is okay if it is dissolved fully and flushed out, but could be the source of the degradation otherwise since it could stand in the pipes for awhile.

Part of the problem may be that the downpipe from the drain needs to be longer to accommodate the DW outlet above the trap.

Those combined things may mean the plumbing in the wall will have to be lowered. Should you want to ever install a disposer, it may have to be even lower, or, if you redid the countertops and installed a deeper sink.

 

[JonathanB]

Thanks for the reply. I did some digging and testing. From the floor (not the cabinet floor, but the actual floor) the waste drain is 25 inches high. If I measure from the cabinet floor it's 19 inches. The cabinet height is 36 inches from the floor, so that gives 11 inches or so until the drain and sink would meet. With the sink strainer the sink is 12 inches.

So that would mean the waste drain is actually higher than the bottom of the sink strainer. To complicate things, I had a little look into the pipe, and because there is a window above the cabinet, it appears to go left and not vertical, so I guess lowering it won't be easy considering it's travelling horizontally.

I looked for strainers online and found one which is 2.5 inches vs the 4.0 inch that I already have, but that inch would mean the waste drain and strainer are actually level and flush from the bottom, and I don't even know if it would drain because gravity won't push water that's level obviously.

I'm handy with stuff but this seems to be getting complicated. I'm on a limited budget too. From what I've read online 20 seems to be the normal from the floor in regards to height, but since disposers etc are common nowadays I think 13-18 seems to be the range? So why 25 inches in my sink? Is that an "unusual" height? My sink is only 8 inches or so in depth. I don't think sinks that are like 5-6 inches are common which would give just about enough room for this to drain.

Getting frustrating because my wife thinks I should be able to do it by just changing a couple of pipes under the sink and I can't get her to understand that gravity doesn't go up. She thinks that it was just some blockage in the pipes that were causing the it to drain super slow. Now I can't even get it to drain AT all even if I link it directly from the sink to the drain. It's not angled down, so the water just builds up in the sink. I'm so baffled as to how it even drained before, albeit slowly as hell. It seems impossible.

 

[Reach4]

See https://terrylove.com/forums/index.php?threads/under-sink-really-high-waste-line.80803/

You may also have partially clogged drain in the wall. What is below that? If you have a basement, there can be a fairly easy cure for that.

Opening the wall and installing a new sanitary tee at the ideal height sounds hard, but it may be the way to go.

 

[JonathanB]

No basement. I don't really know what is what and were. The cabinets are up against a wall that goes outside and a window above. All I know is the drain pipe coming out of the wall seems to be an elbow that goes left through the rest of the 8 ft of various cabinets behind the wall. I was thinking if it was vertical I could just cut through the wall, cut the pipe above the T and then lower it, by adding new pipe and couplings, but the thing going horizontal kind of prevents me doing that now.

I think so far my only options are to raise the counters, which requires a ton of work, lowering the drain which would be doable if it were vertical with the vent up and the drain down with the T, or somehow getting a sink that's 4-5 inches deep.

I am tempted to just smash through the concrete slab behind the cabinet to reveal the pipes more clearly, but once I do that, there's no going back or patching it like it's drywall.

 

[Reach4]

What is that shallow 2.5 inch basket that you found?

You can make a water level by filling some clear plastic tubing with bubble-free water. See how much lower the bottom of the wall hole is than the bottom of the sink.

Find a 1-1/2 in. Plastic P-Trap with Reversible J-Bend. Play with that. I don't know how the dishwasher is going to get along, however.

 

[Layla-Gail O'Brien]

You'll still have to open the back up a bit more; but, by using a combination of fittings you can lower the trap arm & get the proper 1/4" slope while extending & reconnecting the existing horizontal vent pipe that goes around the window, & should be able to fix your problem. What material & sizes of pipe are you dealing with?

 

[Reach4]

You'll still have to open the back up a bit more;

Huh? If he opens the back up, he could put in a garbage disposal.

 

[JonathanB]

It's 1 inch lower (bottom of the hole)

You'll still have to open the back up a bit more; but, by using a combination of fittings you can lower the trap arm & get the proper 1/4" slope while extending & reconnecting the existing horizontal vent pipe that goes around the window, & should be able to fix your problem. What material & sizes of pipe are you dealing with?

So this is what I can tell. I shined a flashlight into the drain hole.

It seems it goes one way. It's like a =======O

Where O is the pipe coming out of the wall and it goes left. I don't know how did this whole plumbing in this house but something doesn't feel right. I am not a plumber at all, so I don't really know the ins and outs of the whole thing. Changing some pipes and a trap is one thing but trying to understand where the vent is in this setup, well I don't know. I figured it worked like this... that when water is pushing through air needs to vent somewhere on the other side the water goes to prevent gasses and smells coming back in. I have a bad feeling that I am going have to smash through the concrete to figure out what's going on.

Is the vent supposed to be somewhere else down the line? Like, from the looks of it, if it is then the stuff would go down somewhere else and then get vented somewhere else in the house, but wouldn't it make more sense to put in a T at the arm location rather than somewhere else? I am tempted to call a plumber but 1) this isn't my house and I won't be paying for a plumber to fix my mother in laws issues that I guess should have been fixed a long time ago and 2) I've spent so much money already fixing this place even though I'm just renting it, and 3) mother in law just told me she had to pay X back in taxes and is just as broke as me, so basically everyone is expecting me to fix this issue with minimal costs and pressuring me to do it in 24 hours cause we have no kitchen sink working right now. Wife is hanging up on me saying "Just fix it yourself" when I try to talk to her about it at work.. *sigh*

 

[Reach4]

Changing some pipes and a trap is one thing but trying to understand where the vent is in this setup, well I don't know.

The vent and drain are probably very near the left edge of the window. There will be a santee where they all join.

If you open that wall, add a cleanout while you are at it.

But seriously, if you struck a laser level line to the inside bottom of the hole opening in the wall, you think that would hit a ruler touching the bottom of the sink at about the 1 inch mark?

 

[Terry]

So your drain goes to the side, which means lowering the trap arm may be very difficult.
The slow drain may mean that to speed it up, the line will need to be snaked. The drain at the wall is lower than the sink basins. The water should be going down, unless the pipes have too much muck and grease in them. Getting baskets with less depth will help for making connections underneath.

 

[JonathanB]

Ok, thanks all. Tomorrow I am going to go get some extra fittings, etc and see if I can get this going again without digging through the walls.

 

[Layla-Gail O'Brien]

Oh...your drain is to the side...not the vent! Well, that DOES create a problem. I think Terry has the right idea.

 

[JonathanB]

Ok, plot thickens. I took a level from the bottom of the sink strainer to the waste line. The drain arm is actually 2 inches HIGHER. That is, the bottom of the drain (lowest part) is higher than the lowest part of the sink. When I start adding plumbing, that's at least 3 inches higher, before I even put in a trap. When I connect it to the drain, it goes UP at an angle, quite an angle too, that's with minimal pipe. I can't see how it's even possible to drain upwards when the drain is higher than the lowest part of the sink?

 

[Layla-Gail O'Brien]

Ok, plot thickens. I took a level from the bottom of the sink strainer to the waste line. The drain arm is actually 2 inches HIGHER. That is, the bottom of the drain (lowest part) is higher than the lowest part of the sink. When I start adding plumbing, that's at least 3 inches higher, before I even put in a trap. When I connect it to the drain, it goes UP at an angle, quite an angle too, that's with minimal pipe. I can't see how it's even possible to drain upwards when the drain is higher?

Is there a point you can get to that's lower on the drainline to reestablish a correct connection?

Are you dealing with metallic pipe?

 

[JonathanB]

Is there a point you can get to that's lower on the drainline to reestablish a correct connection?

Are you dealing with metallic pipe?

All the pipe I've been dealing with is metal, the arm coming out of w/e is really nasty looking too, on the out and inside. Underneath the sink i literally tapped the pipe coming down into the trap and it snapped right off and water came out from the top of the sink, which made me believe that the water was just sitting up there all the time. The dishwasher hose was connected below the drain too. I have to find the drain line where it goes vertical at some point and I guess lower the tee there, that goes to the drain coming out of the wall near the sink, but finding it is really difficult with this whole kitchen and cabinet setup. It's old, and put together all crudely so if I start taken it down, it's not going to go back together easily, or at all. I am also working in a limited space. This is turning into a nightmare.

I called my mother in law and she said that when she got the house an inspector took a look at the plumbing under the sink and said it's all good, but I can't see how it was all good when it's higher than the sink? No wonder it never drained properly and my theory now is something was able to suck it down through some sort of vacuum and when I removed all the pipes and installed new ones under the sink, that vacuum has gone so no matter whatever setup I do it won't drain, period. I have put in an inverted J pipe into the drain and poured water down the top of the whole and it flows down there OK. I put about 50 oz of liquid and it flows fast and fine, so I guess the problem si the drain being higher that prevents gravity working.

So to sum it up. Sink drain is lower than waste drain, by inches. Level won't lie, it shows clearly that I would need my sink to lose 2 inches to even be level with the drain, so most likely my sink needs to be 4-5 inches higher or drain needs to be several inches lower. Small sink is out of the question, since 8 inches is ok, and saving an inch by changing the strainer still leaves the waste drain higher by an inch.

What is the prognosis on this whole ordeal? Is it doable myself at this point? And what is the cost involved roughly?

 

[Layla-Gail O'Brien]

Your dealing with metallic pipe, that's good! A scanner tool (like the Bosch Digital Wall Scanner with Modes for Wood, Metal, and AC Wiring) costs about $60 & can locate metallic pipes within the masonry wall p to about 4" deep. [I have a feeling it'd be a good addition for your toolbox too].

You can go back with metal or PVC/ABS pipe for the correction.

 

[Reach4]

So to sum it up. Sink drain is lower than waste drain, by inches. Level won't lie, it shows clearly that I would need my sink to lose 2 inches to even be level with the drain, so most likely my sink needs to be 4-5 inches higher or drain needs to be several inches lower. Small sink is out of the question, since 8 inches is ok, and saving an inch by changing the strainer still leaves the waste drain higher by an inch.

Would the pink line E be a horizontal line, or green line G, or what?

 

[JonathanB]

Would the pink line E be a horizontal line, or green line G, or what?
View attachment 52701

Because the sink drain is closer the way I angled the camera changed perspective a lot. The drain appears to be slightly slanted down, not up, so it might be 1/4 angled. To answer your question if I understand correctly. Exact center might be roughly D from level.