I do NOT need to smell that snake again...
February 26, 2007 5:28 PM   Subscribe

I have a dual sink with a disposal, and something is causing the water to back up into the other sink.

I've done everything I think I can from reading various DIY forums and other question/answer sites. My kitchen sink has dual sinks, one with a disposal unit, and one with a regular drain. Even without running the disposal, I can run water into the sink, and eventually it'll fill up, equalizing the water on both sides. It takes hours to drain.

I pulled out the U shaped pipes under the sink in front of the Y joint, inspected them to ensure that they are clean. I used the allen wrench on the disposal unit to manually move the grinders and clear any obstructions. I bought a power-snake at the hardware store, and was able to successfully insert about 15' of it. Even when I pulled out the snake, it didn't seem particularly dirty. The head of the snake wasn't dirty at all.

I've used various draino/liquid plumber products to no effect. Hot and cold water doesn't make a difference. The sink fills up pretty rapidly when I start running the water, so I assumed that the clog, if there is a clog, would be close to the surface.

Might this be related to the awful, snowy weather we're having locally? Is there some sort of air pocket in the line that isn't allowing the water to drain effectively? How would I go about treating something like that?

All of the local plumbers are booked for days, so I need a solution pretty soon before the dirty dishes rise up and attack me.
posted by thanotopsis to Home & Garden (13 answers total)
Where does the water go when it leaves the kitchen? And are any other drains in your house backed up? If there is no obstruction between the sink and the drainpipe as far as the snake can go, then there must be an obstruction further on. If no other drains are affected, the obstruction must be located before they enter the main drainpipe.

Do you have a basement? If so, you should be able to find where the drain from the kitchen enters the main drainpipe in the basement. There should be at least one cleanout plug on the main drainpipe. You can remove it with a large wrench. It may be messy, though, if there is water still backed up. Use your snake down there.

The Reader's Digest Complete Do-It-Yourself Manual has very clear instructions, with photos and diagrams, of how to do this kind of repair.

Good luck!
posted by brianogilvie at 5:41 PM on February 26, 2007

I had the same problem at my 2nd floor apartment and the plumber solved it with a snake: a really long mechanized snake. The blockage was way outside my unit. It was so far that the problem could easily have been the work of a neighbor.

So, you just need a longer snake I'm betting. Book a plumber and start eating out till it gets fixed would be my advice. It's probably not good advice but it's all I have.
posted by chairface at 5:43 PM on February 26, 2007

Response by poster: But wouldn't it take quite a while for the water to back up if the clog was so far away from the sink? My water comes right up and sits and stares at me whenever I run the faucet.

I know where the drainage pipe is in the basement...I'll try there next. My kitchen already looks like an operation gone bad, and the unfortunately side-effect of having a bleach-based chemical solution is a ruined black t-shirt.
posted by thanotopsis at 5:48 PM on February 26, 2007

Response by poster: Ok, I've got 3 prospective drain pipes in the basement. I had my son run water in various sinks and appliances around the house, and I think I've isolated the one that's responsible for the kitchen sink.

There's no water in it. It's wet, and it smells like the rest of the piping smells (i.e. old rotting food from the disposal) where I pulled it out from underneath the sink, but there is no water in it. I rechecked the sink up in the kitchen, and there's still standing water there.

Something's happening in between the sink and the drainage pipe, then, I would conclude.

However, the snake run at full length on either the entrance to the drainage pipe or the Y joint underneath the sink yields nothing.

Is it possible that the water's not even entering the Y joint through some principle of physics or air pressure that's trumping the natural inclination to, you know, obey gravity?
posted by thanotopsis at 6:05 PM on February 26, 2007

Is there another sink on the same line that is backing the water into yours? Our 1920s plumbing does that all the time. Maybe your sink drains, but the volume from the neighbors backs you up?
posted by mrbugsentry at 6:19 PM on February 26, 2007

Best answer: An effective techique for clearing most types of grease clogs in dual kitchen sink setups, is to get two, yes, two plungers (one for each sink) fill both sinks with a couple inches of warm water, and then plunge both sides of the Y connected drain lines, at the same time, together.

You have to know how to plunge effectively, which involves
1) filling the plunger cup entirely with water (which is effectively incompressible) before beginning plunging action.
2) developing an maintaining a water tight seal around the plunger cup (easier to do with the extended collar (funnel bottom) type of cups), and
3) plunging by developing a smooth stroke of average velocity, which imparts maximum momentum to the column of water you are pushing. It's the alternation of momentum of the water column you are plunging, back and forth in the pipe, that moves the blockage, not the pressure you develop.

Plunging both sides of the Y connection effectively develops tremendous downstream force, up to hundreds of pounds of pressure per square inch of pipe cross section. You can even pop the packing out of packed soil line joints if you get too enthusiastic, so don't wail on the problem with all your upper body strength, unless you can visibly check the soil line for leaks.

But if this technique doesn't move the block, you definitely will need a mechnical clearing device such as a snake.
posted by paulsc at 6:34 PM on February 26, 2007

Re: Why it would fill up quickly

Because it never gets fully empty. At least that's what I assumed.
posted by chairface at 6:41 PM on February 26, 2007

Response by poster: Paulsc: That's a good thought -- 2 plungers. I've got an additional problem, which is the drainage line for the dishwasher that comes into the side of the regular drain on the sink. It's got an overflow outlet at the side of the sink. If I plunge too much, water just comes up out of that. I have to figure out a way to stop that up.
posted by thanotopsis at 6:44 PM on February 26, 2007

It's no mystery, there is a clog further down the line. You need a longer snake.
posted by lee at 6:48 PM on February 26, 2007

We had the same problem with our double sink before we replaced it. Mr. Lucinda explained it to me now, like this:

The sink on the right (without the disposal), the pipe went straight down. The sink on the left, the one with the disposal, was joined to the sink on the right's pipe by a ninety degree pipe.

However, the ninety degree angle pipe was jammed too far into the straight line pipe, so it stuck into the straight line pipe and would block the flow of water down the drain.

The ninety degree angle pipe had stoppers on it so that it wouldn't go into the pipe, but whomever assembled it just jammed it in past the stoppers.

The water couldn't flow down the non-disposal sink as quickly (since the end of the pipe was in the way) and the sink would fill up.
posted by Lucinda at 7:36 PM on February 26, 2007

As others said, the clog is farther downstream, probably in a horizontal section of the pipe as it goes under the floor. A plunger won't work because all you will do is force water up the vent stack to the roof. If you call the Rescue Rooter guys they will fix it in about a half hour for $200 bucks. They will try to up-sell to power scouring but just get the basic snake service and you'll be okay. The best method if practical is to run the snake vertically down from the roof vent. Look outside on the roof above the kitchen sink. There should be a vent stack. If the roof is easily accessible (single story), not too steep and you have a ladder handy for the rooter guys, that might be the best approach because it avoids a couple of bends in the pipe and keeps their dirty equipment out of the kitchen.

If you can do the roof access, then you can connect up your drain pipes and keep the sink filled while they run the snake. That way you can tell when the clog is cleared as it will start draining and the surge will help clean the pipe. Usually the water won't start to drain until the snake is extracted from the clog because the clog just seals around the snake until removed.
posted by JackFlash at 7:53 PM on February 26, 2007

Response by poster: Well, after 3 hours of back-breaking work and worry last night, I finally solved the problem. I was inspired by PaulSC's comment and attempted to make dual plungers work.

After crimping the line that connects to the diswasher so that my efforts weren't completely wasted, I stood up on a chair and worked my upper body strength into plunging the sink. It still didn't work.

I then noticed something: If water is in the disposal sink, and I turn on the disposal, it sucks all the water down and the water goes up in the other sink. Without the disposal on, the water level equalizes. I figured that the disposal was acting as a propeller.

I put one plunger over the drain on the other side of the sink, filled the disposal sink with water, and then turned on the unit. Sure enough, it started sucking the water in. However, with my plunger over the other drain, it didn't have any choice but to push downward into the pipes rather than push back out of that drain. That plunger was bucking like a wild animal, but I held on.

After about a minute, I felt a sudden lessening of pressure, and the water in both drains made a loud sucking noise. I'd beaten the thing.

Sure, I could have burned out the motor in the disposal, and I'd like to think that I would have been able to tell from its labor that it was getting near the breaking point. Right now, I'm just happy to be able to wash my dishes.
posted by thanotopsis at 10:20 AM on February 27, 2007 [1 favorite]

thanotopsis, if I could favorite your comment a million times, I would. My roommate and I have been stressing over our clogged sink (Drano and the like never helped) that is set up very similarly to the way yours was. I just now tried your trick—plunger over the non-disposal side while running the disposal as a blaster—AND IT FUCKING WORKED! We have a sink again and I'm dancing like a cave man over his first kill. Thank you!
posted by carsonb at 5:37 PM on January 22, 2008

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