Ok, so after having emptied the closet, turned on the dehumidifier to "VERY DRY", and training a fan on the carpet, I came home Friday to an almost-dry carpet.
This should not be.
Please refer to the really BAD drawing below of my house floorplan, sorta.
Ok. Over on the right side there, those colored boxes are as follows - The light blue one is the "powder room" or "1/2 bath" - as there only a sink and a toilet and 2 towel bars and a picture of rabbits in there. The green area is the lovely "Fibber McGee" closet that houses my cleaning machines, games, extraneous stuff with no other place to live, and my winter coats. The bright MAGENTA area is where the water heater lurks, and the yellow bit is where the furnace lives. Those bits that look like Madonna's Tits, or really sad mountains are bi-fold doors, and the other triangular bits are other doors. The livingroom/diningroom area is to the south and west of the colored spot, the laundry is north and the kitchen is northwest. For some reason, "Paint" is not letting me alpha-label anything, so you will have to use imagination.
Now, the really wet area was right in front of and behind the bifold doors in the "Green" zone, thus suggesting the culprit was, in fact, the water heater. However, that area is now quite dry - perhaps just a TINY bit dampish yet due to the massive amount of soak-down it had previously.
The interesting bit to all this is that I am unable to turn off the water supply to the water heater, because the valve is frozen in the "ON" position - doubtless rusted that way after over 15 years or more "ON".
The area beneath the heater appears damp also, but not soaked, nor is there a "puddle", and brave soul that I am, I took an extra-long really hot shower this morning to test this out. Hmmmm you may say. I must say, I have been saying "Hmmm" as well.
Now, we look to the north, to the toilet tank that has issues. I manually turned off the inflow to that on the day I discovered the cats were not possibly to blame for the flooding carpet (they're fairly small cats - they'd have to have peed non-stop for over 24 hours to get the carpet that soaked...) At that time I also started up the dehumidifier and fan combo. As of this morning, I've emptied that dehumidifier about 4 times now. The carpet is almost completely dry.
I am beginning to suspect it is that bad water tank in the downstairs commode - which will be a HELL of a lot cheaper to fix than replacing a water heater. A very GOOD water heater, btw - a 40 gal. Rheem "Fury" that does an excellent job for not a lot of cash. I really would hate to have to replace it with something lesser.
So. As of this morning, I have (mostly)dry carpet, a non-functioning commode, 2 pampered pussycats, a seemingly innocent water-heater, and a livingroom full of crap that I really do need to sort through and decide whether I want to keep it, freecycle it, or give it to the BFI man.
I'd have pictures of my veggie/flower garden for you, but I can't find my spare USB cable. Perhaps later.