Rosetta, if your washer drain pipe connects to the main 3 inch dump pipe make sure you have a end gate on the dump and have at least one gray tank valve open. I forgot to do this twice, once with the original OEM flooring and once two days ago with new vinyl. The mess was easier to clean up the second time
. I put the clothes in the washer and said to myself "self, don't forget to open a gray tank gate" and promptly went out the door and forgot. The running water sound was the WAKE UP call... Dave P.S. congrats on the new toys