We recently just moved. A week in. It's been raining on and off for the past few days. This morning I noticed a huge puddle in my laundry/half bath. Couldnt find the source. An hour ago I heard a gushing of water and ran into the bathroom and notice water coming from the washer drain pipe behind drywall. Currently we don't even have a washer hooked up. Haven't since we moved in. Has anyone had this happen or know what it could possible from???

** the pipe comes from the the wall to the basement where the water tank is. That's a bit damp too.

  • Is the water tank your sump?
    – Valkor
    Commented May 10, 2019 at 16:50
  • I assume the water tank is your water heater? Can you see where the washer drain runs to?
    – JimmyJames
    Commented May 10, 2019 at 18:25
  • While you're waiting for a plumber or to get the snake, you might want to block or temporarily cap your washer inlet. This will at least help you keep the drain from backing up on your wall and floor. Commented May 10, 2019 at 18:55

2 Answers 2


You have a combination of a partial blockage somewhere in the drain system combined with something that causes too much water at one time to come through. Since this doesn't happen "all the time", you have to figure out what item(s) trigger the problem. The solution will depend on where the problem is. Water will always flow out of the lowest possible open location, which in your case happens to be the washer drain pipe.

  • Washing machine - You can rule this one out since it isn't connected.
  • Dishwasher - If this happens only when you run the dishwasher, then the problem is in drain pipe shared between the dishwasher and washing machine. If it happens other times as well then the blockage is farther along.
  • Bathtub/shower - If this happens only when you drain a full tub or towards the end of a long shower, then the blockage is in drain pipe shared between the tub/shower and the washing machine drain.
  • Sump Pump - This is the one possibility that would be related to recent rain. If you have a sump pump then every time it activates it will pump a large amount of water very quickly (like a dishwasher or washing machine draining) and that would match the pattern your are seeing. If you don't have a sump pump then this probably has nothing to do with the rain.

The most common solution to a drain problem is a snake. The catch is that the snake needs to be long enough to reach through to the blockage. A blockage that only affects one part of the house is likely to be close - often within reach of a 25' handheld snake. But if it is a longer distance to the clog then you will need to either rent a bigger snake or call a plumber who has one (and who knows how to use it). The bigger snakes are a bit tough to handle - I rented one once (and was successful) but usually if it gets to that I call a professional.

There are also chemical and air pressure solutions. They may work but a lot depends on the location and type of blockage. I find that a partial blockage (which it sounds like you have) is easiest to clear with a snake because the chemicals tend to pass a partial blockage without sticking around long enough to clear it.

  • And the kinda obvious (if a bit unpleasant to contemplate) "flushing the toilet(s.)" In many places sump pumps should not be (are illegal to, but people will do it as they figure it can't be seen in their basement) connect to the sewer. In others (becoming more rare, as they contribute to untreated sewage discharges during rain events) it's fine.
    – Ecnerwal
    Commented May 10, 2019 at 16:41
  • 2
    In my personal experience there are still many old high-volume toilets in the wild, even though standard flush sizes have been shrinking. It's not an object most people care to mess with unless they are remodelling the bathroom or it's hopelessly broken. Mine appear to be 47 years old... it would be nice to update them, but it would also be a pain, without a doubt.
    – Ecnerwal
    Commented May 10, 2019 at 17:02
  • 1
    I have found replacing a toilet to be one of the easier jobs to do, at least as long as the original toilet wasn't something non-standard. Commented May 10, 2019 at 17:11
  • 1
    @Ecnerwal Even if you are allowed to hook up to the sanitary sewer with your sump, I highly recommend against it because if the sanitary sewer backs up, the sump will pump water up the stack and overflow at the lowest drain(s)/toilet(s) in the system.
    – JimmyJames
    Commented May 10, 2019 at 18:24
  • 1
    @JimmyJames Which is a working theory as to what may be happening here. Commented May 10, 2019 at 18:27

You have a partial block somewhere down the line. Water from somewhere else in your house is trying to drain out of your main sewer line, but it can't. Your drain pipe briefly filled up to the level of your laundry room drain and spilled out.

Call a plumber to clean your drain.

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