Assuming you have a Splendide combo unit, remove the top of the machine and then start it briefly to locate where the leak is. There are some hose connections inside the unit that may have come loose. Worse case is the water distribution assembly (big white plastic part on top under the cover) has a crack or defect.
If the unit had been run, not winterized properly and subjected to freezing temps, that part can fail internally. My screw up a couple of years ago taught me that.
Once you find and fix the leak, install a drain pan under it.
About the water heater, if you filled it with the valve open until water spewed out, you've overfilled it and it will spill out. Drain some water out of it, turn the supply back on, and then close the valve when you first get a drip from it. It needs an air gap at the top to function properly.
Back to the washer, here's some photos of mine with the top off and the drain pan I installed after the leak occurred. I actually had water dripping off the king pin
. Got it all dried up, but the overhang panel warped some. First connection I'd check is under the water distribution assembly. It's a soft hose with a wire clip holding it in place. The other is down lower where the actual pump is located. Also check your supply hoses are snug and the valves in the wall fixture don't leak. Be sure the drain hose from the washer is securely attached to the wall drain, too, and that there isn't a problem with that drain line in the wall.
With our floorplan, I was able to route the drain pan hose from the closet, under the dresser and down into the hydraulic/battery cabinet below.
Sent from my iPad using Tapatalk