Washing machine standpipe overlfows

Old 01-12-20, 03:12 PM
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Washing machine standpipe overlfows

Standpipe overflow.
We have lived here for 2 years. Our new washer drains into a brand new standpipe that is higher than the washing machine. The plumper said all the pipes are to code, looks like new large piping and everything looks fine.
He hooked up a garden hose and shoved it down the standpipe. We ran it at full blast the following day after the back up for in total for 10-15 minute. He said we ran so much water down there that he was confused as to where the back up was?
For precaution, he snaked the line all the way out to the main sewer line.
So we are a bit paranoid as to know when this back flow will flood our laundry room again.
He said it was probably a back up that we had, but that he was not able to see it the following day. But from what I explained to him, he said it must have been a back up.
However is also said it is possible the main city sewer line backup, which effected our place? The back up worked it was to us.
I can buy a sensor to set off an alarm when this happens again, but is there something we can do to feel confident this will not occur again or catch it prior
I looked into a valve that will close the standpipe if there is overflow. But this seems to be frowned upon?
We can't drain this into a sink where we would be able to tell if it was slowly draining.
I am trying to see if anyone has advice as to how to tell when we should expect a flood again?
We did not see any drain issues prior? Knowing if your washing machine is draining slow is not really easy to tell? The second flood we had we never even used the washing machine which tells me the entire system must have been backed up.
So this is a bit frustrating to figure out some type of heads up before this floods sewage into our laundry room again.
Thanks for you help and advice.
Old 01-12-20, 03:19 PM
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Have a plumber install a sewer check valve at the point your sewer exits the house.
PJmax voted this post useful.
Old 01-12-20, 04:17 PM
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When you had the second flood..... where did the water come out ?
If you have a problem with the main sewer backing up..... the water should be coming out at the lowest point in the system.
Old 01-14-20, 10:48 AM
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Did the new washing machine ever work with laundry load size set to extra large and without overflowing the standpipe?

Some models of machines may pump out water too fast for standpipes that don't meet code or standpipes with a little lint or crud at the bottom to drain properly without overflowing.

The roof venting for that part of the drain plumbing may have become clogged with a bird nest or other debris, resulting in back pressure that retards the flow from the standpipe.
Old 01-14-20, 02:04 PM
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Washer pump a lot of water out in a hurry. Have found that most sinks and showers will drain when a washer will back up. The problem has always been a blockage down stream from washer.
Old 01-14-20, 06:17 PM
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I am curious what size pipe was used for the new standpipe.
Old 01-15-20, 05:08 AM
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I looked into a valve that will close the standpipe if there is overflow. But this seems to be frowned upon?
This is not an uncommon thing to do. As I recently made note in a recent post I made about my son's new home.
Also that is why we are considering putting in a stationary sink, even though it must be a pump drain system.
Our washing machine will fill the tub to almost 3/4 of it's capacity when draining. Albeit, I have an 1 1/2 drain.
Old 01-15-20, 07:31 AM
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The washing machine hose must not fit tightly or be sealed into a standpipe.

An advantage of draining the washing machine into a laundry tub is that the water can take its time going down the drain pipes.

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