QUESTIONA friend has water coming up the house slab into the tile grout lines in the utility wash room. It only happens when the washer drains. Removed the baseboard and lower part of the drywall to see the drain pipe. Ran the washing machine and saw no water in the wall.
ANSWERANSWER - If the water is consistently coming up through the tile grout joints when the washing machine drains, and you don't see any water in the wall at the drain pipe, then the water from the washer must be leaking or draining below the concrete slab.
You need to follow the drain pipe down further where it enters the sewer or septic tank. A plumber should have tools like a boroscope to that they can use to locate the breach in the drain pipe.