Washing machine drain line backs up

A. Acid is not appropriate for metal drain lines. Lye type drain cleaners like Drano [affil links] or Liquid Plumber are more appropriate, although dangerous to people. This isn't a plumbing forum, but have you considered the possibility that roots have penetrated your drain piping? If so, new drain lines is the answer. Can you put a sock or stocking, or more formal filter in the discharge to capture the lint? Is it possible that you have created an air lock in the drain?

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A. Well, seeing as I have the same problem myself, I guess I'm an "expert" :-)

I used duct tape to connect the drain hose to the drain pipe so the water can't escape -- see if that helps. Not the right answer, of course, will probably void your warranty, and maybe a code violation -- but it works for me on my decades-old Maytag.

Here's the real problem possibly: all drains require vents and your washing machine drain may not have one. Your bath, toilet, sinks, basins, all have vent pipes going up through the roof. When water needs to go down one of those drains, it just pushes the air that was in the pipe up the vent pipe. When you have no vent pipe, there's no place for the air to go to get out of the way of the water, so it has to "push back". Why doesn't the air just go down the drain pipe to get out of the way? Because air is much lighter than water, it keeps fighting to "float" back up the pipe. A plumber may have to install a vent. Good luck.

A. Hi, Stephanie. You have your plumber put in a vent pipe, which is probably required by plumbing code anyway -- or you live with it, or you do unadvised duct taping things to minimize the leakage :-)

A. You can see better drawings in a home handyman book, Tracy, but every plumbing fixture including a washing machine should have a trap and a vent. The trap keeps sewer gas out of the house. Good luck.

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A. Look into an Air Admittance Valve .
This will let in air without have to run a vent up through your roof. Sure old timers will tell you this is "band-aid" plumbing but sometimes you can't vent up. Just remember the AAV will go bad at some point so make sure it is accessible. They are simple to add. Of course you should check to see if it is 'allowable' by the code in your area.

A. I had the same problem but it turned out to be roots. Watch out for trees near your sewer line. They always are the main problem. I have worked for a Public Works Department for 30 years so you think I would have figured this one out :-)
But no, the trees were 50 ft away.

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A. Regarding washer machine drain problems. I just installed a Studor Mini-Vent today and am hoping this corrects the problem. I had to cut into the 2" line and install a tee in order to do this, but it was very easy.

If this doesn't correct the problem I am going to install a laundry tub and allow the washing machine to drain through it. This should slow down the water drainage and hopefully solve the back-up problems that we have been having as well. I have tried snaking the drain, about every type of drain cleaner and nothing worked. We also had an older washer and never had any problems until we had to replace it with a new one.

I will update this to let you all know if the mini vent works or not.

A. Most of the drainage problems espoused here could be simply resolved by eliminating the usage of tub-type washers and employing front loaders. The latter use 1/3 the water of a top load machine, and using less of anything is a good thing these days. One-third in, one-third out.

Simple, but difficult and unreasonable if your top loader was a recent purchase. Replacing an older machine will pay for itself after several years -- less water, less water to heat, plus more gentle action on your clothing.

A. When water comes right out of the washer as it's filling, it's a sure thing your hose is too low. this creates a siphon which pulls water down to the level of the outlet of the hose.

Solution: raise the hose. it should dump water at or a little above the level of water in the tub. measure from the start of the tub opening to the top of the washer, measure from the top of the washer to the floor, and subtract the smaller number from the larger. that's the height the hose outlet should be.

It will be higher on a top loader than a front-loader, unless you have an unusually high pedestal. washers have a small drainage pump that will make up the difference.

A. My washing machine has also been overflowing out of the drain tube. The wall rotted, I tore out all the rot, replace the 2 x 4's with pressure treat, and instead of using sheet rock in the laundry room I decided to use plastic bathroom board.

I have a 25' snake. I snaked the p-trap and came up clean. I went on the roof and snaked the vent as best I could - came up with mud looking stuff and hair.

I ran water hose full blast through the drain and through the vent and it did fine - however, the washing machine still backs up.

To reduce the flow rate I took the rubber drain hose off and stuck a metal washer in there - at the end where it connects to the washing machine - the metal washer is large enough so that it won't fall into the washing machine and won't get pushed through the drain hose. It fit perfectly and reduced the hose size about a third - and it was enough to fix the problem.

I sealed all the gaps at the drain / water supply box with Great Stuff expanding foam, and used caulking to seal all the base boards so next time it overflows it will stay on the tile floor rather than being able to sneak back in the wall.

Hi, Brian. Different installations have different problems, but to me it sounds like in your case you still have an air-lock despite the main vent. Picture this, although perhaps exaggerated:



If a pipe has any unvented high spot, air will collect in it. Think about what happens when water tries to flow in such a pipe: the only way water can go into the air locked area is by driving the air out. But how are you going to push that air -- that so desperately insists on floating -- down below the water at the other end of the air lock? You can't. If you have a situation anything like what is pictured, you have to fix the routing or have a vent at the high spot to let the air escape from the pipe. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 19, 2010

A. I fixed the same issue for a neighbor

She bought a new washer that discharges water at a higher rate, causing her drain line to overflow. I cleared the line about 15 feet or so and no luck. I tried every way to fix it but just came to the simple, but not as neat, way of discharging the water into a plastic mop sink with a p-trap discharging into the drain line. This does the job and adds a mop sink in your garage and if you need to soak,clean etc you don't need to go to the kitchen. Do not discard chemicals or paints down the mop sink, not good for your cast iron or the ocean.

MOP SINK: $49 dollars plastic hardware: $15 dollars little bit of cutting and connecting handyman/plumber: one to two hours of labor. 25 to 80 per hour...all though you can do this yourself easy. ask your local hardware/home improvement personnel.

You might have to relocate the washing machine and dryer: extra hardware/material....not much but this will add to the labor per hour part. If they know what they are doing just two hours max

A. We bought a newer washing machine and our drain could not handle the flow, it would back up in the sink and overflow. We have 2" diameter drain pipes and vents. Finally solved the problem by renting a power snake, the one that works like a power drill. Threaded it as far as it would go, locked it and slowly went back and forth to clean the walls of the pipe. The drill motor rotates the snakes which beats against the pipe walls cleaning them. Slowly did this in one foot intervals. Locking the snake, pushing in and out, unlocking withdrawing a foot or so, relocking and pushing in and out with the drill motor rotating, until the hole drain was done. Takes some time and effort, but it did the trick, cleared drain and only cost $22 to rent the power snake. Note: Threaded the snake through just below the sink drain in our case. Good Luck.

A. I had this same problem and puzzled on it for six years. I tried everything: store-bought drain cleaners, home-remedy drain cleaners, plumbers, boiling water, everything. Then it finally dawned on me that the flow rate from the washer was more than the drain pipe could handle. I bought a washer drain hose that was narrower than the one on my machine. I clamped one into the other, effectively reducing the flow from about 1 1/2 inches (in diameter) to about one inch. This worked instantly and cost me about nine dollars.

Now I just need to replace all that rot caused by this problem. Wish me luck.

A. House is 72 years old. It has copper pipe that goes into cast pipe. The 2 inch drain from the washing mashing connects somewhere under the kitchen sink. We figured this out by removing the kitchen sink clean out and running the washing machine. Water came out the kitchen sink drain clean out. We snaked it and the problem appears to be solved. Note. We had to remove the short extension on the kitchen sink drain clean out to get the snake to go down the pipe. We also flushed water down the pipe and watched debris go by at the septic side.

Hope this helps ...