Hello, I live in an apartment in the basement, and every time my upstaires neighbor does their laundry, when their washing machine drains, it overflows into my apartment through my drain pipe, but when I do my laundry it does not do that, I was wondering if there is anything I could do to stop that or will I need a plumber to come in? And why does this happen?? Thanks for any help you can give,
Sincerely
Melissa

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And why does this happen??

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Because there is a restriction or partial blockage in the main drain line.

It does not overflow when you use your machine because your machine is older than your neighbor's. The newer machines pump out the water much faster than older ones.

Call the apartment maintenance office.
The main drain needs to be snaked to clear the blockage.

As a temporary fix, seal the connection between your washer drain hose and the drain pipe with duct tape.

Harold nailed it! Another reason the neighbors washer overflows from yours is the added velocity it picks up coming down from the second floor. The solution would be to snake the drain from the downstairs washer. Good luck, Tom