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Germy Water in Dishwasher

03/23/2013 9:27 PM

Some dill weed from a dill pickle jar was ground down the garbage disposal which plugged up the drain pipe. With the pipe clogged, running the disposal pumps water out of the dishwasher drain pipe. The water then flows under the sink, leaking into the basement ceiling and dripping through vents, etc. I remembered an "Old House" episode where they said the separate dishwasher drains aren't used anymore. I capped mine, and plumbed the dishwasher into the disposal with a short piece of rubber hose with clamps made for that purpose. Why the dishwasher has a 3/4" output and the disposal has a 1" input is unknown to me.

The leaking problem is fixed, but the pipe is still restricted after a snake and baking soda with vinegar was used. In time the bacteria will do the job. Meanwhile, when the dishwasher drains, water comes up into the sinks. That, at least, is an indicator of a problem. When the drain cycle is over, the water drains back down into the dishwasher. That is where the germy water comes from. If my dishwasher has a check valve, it isn't working. On the next cycle, that germy water is pumped all over the dishes. In some places in the cycle, when the water drains, it is also pumped onto the dishes. That is bad design IMHO.

I seem to remember they installed an anti-backflow valve to solve this problem. What is your experience with these? Any recommendations?

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#1

Re: Germy water in Dishwasher

03/23/2013 9:50 PM

I used Liquid-Plumr foam quite successfully. It is intended for partially blocked pipe. You can make your own version of the regular stuff, google the ingredients, but the foam works well on partial clogs.

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#2

Re: Germy water in Dishwasher

03/23/2013 10:56 PM

I recently installed a dishwasher, and the directions were very specific about looping the drain hose, (from dishwasher to sink drain), above both the sink and the dishwasher. It prevents the type of backflow you are describing.

Like this:

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#3
In reply to #2

Re: Germy water in Dishwasher

03/24/2013 1:23 AM

My Dish washer has that loop, the cupboards even do not allow me to install it any other way. Then I had a smell problem and water left in the dishwasher. apparently a blockage. I got rid of it by applying pressure to the outlet hose and I scooped up all the dirt inside the dishwasher. A back up valve would have prevented me from doing so.

The other thing was that the drain from the sink was partially blocked. After a good chemical clean everything works and there is no smell anymore nor water left in the dish washer.

Its lots of fun to get it back to work and lots of brownie points can be earned.

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#4
In reply to #3

Re: Germy water in Dishwasher

03/24/2013 1:29 AM

Bownie points are good; especially when they're easy.

Back to the OP: The blockage is likely in the P trap. Maybe just take it apart and clean it out or replace it. Heavier particles settle in the bottom of the U.

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#8
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Re: Germy water in Dishwasher

03/24/2013 7:42 PM

No, I said I used a snake, and to use it I had to remove the trap. It was completely clean. The snake didn't come back with anything either, so the restriction must be more than 50 feet away. I plungered a lot to no avail, but that may be why the trap was clean. I have never found Liquid Plumber to work, but sometimes Draino does. I hesitate to use it because it will most likely kill the bacteria that I want to propagate. If it does not work then the sediment adds to the restriction.

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#11
In reply to #8

Re: Germy water in Dishwasher

03/25/2013 10:23 AM

I think you can purchase the bacteria and added back. I believe it is available for septic systems.

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#12
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Re: Germy water in Dishwasher

03/25/2013 12:26 PM

Try using some sodium percarbonate. It comes in a powder and is a high strength peroxide that is safe to handle as long as it is not wet. Follow the manufacturers suggestions for handling or look for the MSDS facts. The peroxide will break up many fats and biological slimes. It will also force things attached to the interior piping to be detached. No harm to ABS piping. It is also eco friendly. You can even use it directly in your dishwasher mixing it half and half with your normal soaps. The dishes will not only be cleaner but will be disinfected.

For your purposes in the drain, you may want to try rinsing a half kilogram (1 pound) down the drain slowly. Let it sit for 30 minutes and then rinse the drain with cold water. It also works great in water wells with biofouling conditions.

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#15
In reply to #12

Re: Germy water in Dishwasher

03/25/2013 1:14 PM

Thanks, I will try that right now.

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#16
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Re: Germy water in Dishwasher

03/25/2013 4:31 PM

It worked! I gave you a GA. Problem is solved.

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#18
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Re: Germy water in Dishwasher

03/27/2013 9:01 PM

Hehe who would have thought! I jump in and completed that GA for Kevin (not that he has not enough) gotta go

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#5
In reply to #2

Re: Germy water in Dishwasher

03/24/2013 9:20 AM

Mine has an anti-syphon valve in the top of the loop, mounted above the sink, I guess its simply a check valve. When I had the problem, I checked everything checkable, I have a disposal, but the blockage was in the pipe to the stack, well beyond the trap. I made a hole in the clog but couldn't completely remove it so I tried the LiquidPlumr, and that finished the job.

BTW, a good way to clean the dishwasher is to run it, empty, with Tang instead of soap. I guess the acidity moves soapy deposits. It does work.

The biggest problem for me is cleaning the drain inside the dishwasher, I though that the pump, would leave it dry so I tried the wand on the vaccum and got a soaking bag of dust to remove. Lucky me, the wet didn't reach the motor.

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#6
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Re: Germy water in Dishwasher

03/24/2013 10:17 AM

Supposedly, our dishwasher has some type of grinder thingy in it that grinds up food debris. I told my wife to not even think about putting anything in there with any food clinging to it. Those gimmicky features are the first to break.

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#17
In reply to #5

Re: Germy water in Dishwasher

03/25/2013 4:39 PM

You are the only one to respond so far an the anti-siphon valve. Specifically I wanted to know whether water comes out of the air gap and wets the top of the cabinets when the pipe is clogged. I would think so. Although this is better than running under the sink unnoticed, I still would not like it. My problem is solved now, but I am curious if the Liquid Plumber you used was a special type.

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#7
In reply to #2

Re: Germy water in Dishwasher

03/24/2013 7:31 PM

I'm not voting on this post because, while a good idea, it may not work in theory. When the pipe is clogged, the water will back up in the sink & there will be no way to get air in the drain hose. The water can be siphoned back even with the loop higher than the disposal. I will do mine that way tomorrow and report back. I was asking about experience with the air gap anti siphon valve as described in my link and shown here.

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#10
In reply to #2

Re: Germy water in Dishwasher

03/25/2013 10:17 AM

A loop will not stop a back flow. After the dishwasher pumps out, their will be a siphon that will pull water back from the sink to the dishwasher. The loop is to reduce the chance of sink water backing into the dishwasher when the sink is drained. A sink full of dirty water because of a clog below the point where the dishwasher drain comes in is a flood waiting to happen. If the dishwasher is run, the sink full of dirty water will be pulled back into the dishwasher after the first pump out. The only way to stop the siphon is an anti-siphon, which has a vent in it to break the siphon so that only water that came from the dishwasher falls back into the dishwasher. This water is expelled after the pre-wash part of the next cycle. Dish washers usually do not use check valves because they clog and stick open because of small food particles.

As for the sizes of the piping, that is the source of a lot of service calls because of clogging where the pipe size reduces. -- JHF

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#14
In reply to #10

Re: Germy water in Dishwasher

03/25/2013 1:13 PM

You are right, and as I suspected. I now have the high loop in place, but it did nothing to stop the siphoning of the dirty water back into the dishwasher. It may have helped for the other things you mentioned.

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#9

Re: Germy Water in Dishwasher

03/24/2013 11:10 PM

Two things come to mind: First, the vent to the roof must be clear, second, where the pipe exits the house there should be two pipes connected for cleanouts, one going in each direction. You said the clog was 50 feet, if you run your drain snake down the cleanout you should be able to find the clog. Cleanouts are sometimes sticking up out of the ground and sometimes just under the surface. Hope that helps, good luck!

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#13
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Re: Germy Water in Dishwasher

03/25/2013 1:09 PM

The vent to the roof must be on the other side of the clog. All other sinks & toilets are working fine. There is a cleanout on the wall near the floor of the basement (about 10 feet below the dishwasher trap). It's difficult to get to with my wife's boxes around there. The snake would have to make a 180 degree turn to go under the concrete to where the clog must be. I don't think that is possible. My snake is only 50 feet, and didn't do the job, but may not have got that far. It likes to twist up. I'm going to look for a longer snake with a larger diameter.

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