I hooked my washer back up after having a new hot water heater installed and now on the drain cycle it backs up into the sink. The washing machine drain is in with the sink drain. Is it a clog? I poured some main drain cleaner down the main drain before I attempted to snake it. This never happened until after the hot water heater install.















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Washer, do put out a lot of water as they drain. It is not unusual for water to pool in the tub, but should drain rapidly. You still have a clog, somewhere. Not being there makes it more difficult to assess.


Time for a licensed plumber to evaluate the lines and vents.
Best Wishes

incredibly bad job to start out with...
water heater can not cause the problem you now have.
you have a clog in the drain.
the check valve in the drain makes me think there were problems from the beginning.
anyway, install a cleanout in that piping and put some hangers on it..
then snake the pipe to see if that clears the clog.

I agree it looks terrible, thats what the house had when I bought it. I'm going to try using a garden hose and the ballon thing and see if it helps.

@packy, Install a cleanout anywhere on the line? And hangers? What kind?

Update: snaked it, sounded like it cleared the line, started the washer, and it is still doing the same thing.

Either replace the check valve, or call a master plumber..

cleanout tee just to the left of that 90 .
as for hangers... j-hooks will do just fine.

short sweep 90's , running threads, undersized piping. I'm a bit surprised it ever worked satisfactory. What happens if you turn the sink on wide open hot + cold and let it run ? Does it back up then ?

It does not back up in the sink if I run cold and hot full force...drains just fine, it only happens when the washing machine drains. I'm so confused because I feel like it should drain down the sweep just fine and not back up..I might install a check valve or check the old one out first to see if its messed up? Its all just really aggravating....


Would replacing that whole run help possibly? I'm just so confused as to why as soon as the washing machine starts draining that whole line all the way back to the sink fills up instantly, yet when I run water from the sink, nothing. If replacing the whole line there, what would I need or what would be the proper way to fix this crappy setup? I apologize in advance, because I know pretty much NOTHING about plumbing. Thanks for all the advice so far though!



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here is two other photos







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