I have a house and back yard. When I switched on dishwasher I found a water leaking/ flowing sound in the laundry room and saw water flooding at back yard. I turn off the main water switch and the sound goes away. What is the probable reasons.

Try killing the power to the washer and turn the main back on. Does water start to flow again? Is the laundry room back to back with the back sode of the washer?

There is dinning area between the dishwasher and laundry room.

City sewer or septic system> Back to you, Tom

OK have you killed the power to the washer yet abd tried truning on the water