I'm having some drainage problems with my washer,I rented a 100foot electric snake and ran it through the washer drain line,and yet my utility sink still fills up when the washer drains.so my next guess is that the utility sink and washer drain system is wrong,so I'm sending a pitcher of the drain system,also this is the way the system was when I moved into the house.so if it's wrong please reply with a drawing of the way the sink and washer drain system should be built.

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Your attachment didn't make it. Did this ever drain normal? Try snaking from the washer roof vent. Put out enough snake to reach the base and 15 feet more. If that doesn't get it then snake from the kitchen roof vent. Good luck, Tom

First thing I would do next is to see how the washing machine (WM) drains. If the WM drains well (doesn't back up into the utility sink or out the washer stand pipe) then the next place to check will be the utility sink...drop Ptrap and snake drain from there...shouldn't have to go too far.

If the WM still backs up then as Tom suggested, try going down the roof vent and keep water backed up in the utility sink so that someone inside can tell you when you start to clear the blockage (water will start to drain from sink). Once you hit the blockage, work the cable back and forth in that area multiple times while running HOT water down the drain (helps clear drain AND clean the cable)!!

Mark