I'll try to make this as simple as possible...When my washing machine is draining, water is backing up and overflowing from a pipe near my a/c unit. It's a pipe that comes up from the floor. There is no water backing up at the washing machine. What's the issue here??

(partial) stoppage in main line somewhere after the 'floor drain'


you will require a service call by a professional drain cleaner or a knowledgeable plumber

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Is the pipe near your AC a condensate drain? If so that condensate drain is not supposed to connect directly to the sewer line.

Is this a new condition - something that didn't happen for a while and now it's happening? If so you might have a stoppage or partial stoppage in your line. If you just moved into this place and noticed this, then it can be many things it could be a stoppage, it could be the drains were not built correctly, it could be the detergent used result in too much suds.