2

Our washing machine drains into a wall-mounted drain. The problem is that as soon as as the spin cycle is over the drain backs up and won’t go down. We have tried snaking it, taking the P-trap off and replacing it and snaking from there. Water will go down if it’s from just a regular pressure hose or cup. But as soon as the washer drains it stops working.

How do I go about fixing this? There not a clog obviously because water goes through. Is it just because the washer drain pressure is too high/ fast? We’ve been using a hose extender and draining out of the back door but I’m so over having to do that.

Improve this question
4
  • 5
    Does the house drain configuration include a standpipe? Can you attach a photo of the drain arrangement, or is it inside the wall? If inside the wall, how high is the drain hole on the wall? Pics please...
    – Jimmy Fix-it
    Commented Aug 10 at 20:08
  • 1
    If you're sure there's no obstruction, the diameter of the pipe is clearly too small for the flow rate the washer is putting out. Since you haven't given us any photos, it's hard to provide a solution. You may be able to add a detention tank, where the washer drains to the tank, and the tank drains to the wall. The tank would need to be large enough to hold the volume of water the washer uses for the largest cycle.
    – Huesmann
    Commented Aug 11 at 14:41
  • Does this answer your question? How can I stop my washing machine drain from overflowing?
    – isherwood
    Commented Aug 12 at 20:04
  • Or this? Washing machine drain pipe backing up
    – isherwood
    Commented Aug 12 at 20:05

2 Answers 2

Reset to default
7

I had the exact same problem with a rental unit.

The solution was, I hired a plumbing company to clean out the main house drain. They said there was a partial obstruction. Once cleaned out, there was no issues.

Improve this answer
1
  • 3
    A washing machine dumps a lot of water fast. the pipes must be completely clean to take it. And large enough. Not sure of the size needed, but might check if the inner diameter is smaller than 1.5 inch.
    – crip659
    Commented Aug 10 at 20:41
0

I'm sorry this is happening, but I think there isn't anything for it other than to pay a pro to come to your house and completely give everything a once over.

They should send a camera down the drain all the way to the street, and they should give you a copy of that captured video.

Otherwise, we are guessing:

  • It could be an obstruction further down.
  • It could be the fact that the washer drain, or a drain it connects to, is too narrow.
  • It could be that this massive flush of water is trapping air somewhere when it fills the entire length of pipe, which would not be a problem with other tests that simply use less volume of water at a time.

The last one is often an issue with modern washers plumbed into a section of an older house without a real or adequate stack to the roof. As pumps got better, that minimal or bad stack arrangement was tested more and more to its limit.

A professional can help determine which one. As any plumber will tell you "there is always a reason for a backup". But those reasons are legion.

Also, a good pro will work with your regional liquid waste management folks to coordinate reports. Often your regional folks will want to hear about strange behaviour of equipment on their drains. I mean, there's the indemnity and responsibility parts of where in a drain the fault lies. But no one is interested in making sure you flood.

Improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.