That looks like a water leak behind the wall. Thinset drying out would be in random splotches not a long downhill pattern like that. It just wouldn't be that regular and it wouldn't be darker near the floor. Water spreads when it hits something and runs downhill, so that pattern is consistent with an active leak. You said "the leak happened when we turned the water on..." Of course it did. If the water was shut off to those pipes and fittings, what would there have been to leak? If I can tell that the wall is wetter near the floor, that's not just a little dampness that you can dry out with a fan or a hairdryer. The best advise here is to turn off the water if you haven't already and remove drywall on the opposite side of the wall. That is probably the only chance you have to save the tile if you still can. Bigger potential problem is that if you don't, the area is likely to stay wet enough long enough to create mold and mildew problems -- even rotting or draw termites. The longer that sits wet or gets wetter, the bigger the problem you will have in cleaning it up and fixing it. I hope we didn't hear from you today because you've been busy doing that. Good luck. This post was edited by lascatx on Tue, Mar 19, 13 at 0:14

Thank you for the reply. I found the pictures of Pharaoh's kitchen (gorgeous!) and also a gallery on a kitchen site that combined the two. It can work! I think I will keep the floor more mellow (maybe a carbonized strand bamboo?) But since I keep going back to that wood, I probably wouldn't be happy with something else. One more decision done. (Didn't realize how much work this would be! Fun, but work.) Thank you for the help.

I actually own both of these stones...I have honed Carrara in my kitchen and butler's pantry, polished Carrara in my master bath and Kashmir white on my dd's vanity and the guest room's bath vanity. First of all...in the two years we have lived here (new build also) none has stained. Not even iced tea, tomato sauce or red wine on my marble. Very slight etching on both types of marble, and no etching on the granite. I will tell you, though, that aesthetically...the Kashmir DOES NOT in any way, shape or form look anything like marble. The stone yard told me it would be a good, durable stone for my elementary age dd and it was the closest granite to marble. No, it isn't. I really wish I had just been brave and done the marble in those baths...it would have given them that "old house" look that I want. Oh well! Don't know anything about quartz, except that I have 1 neighbor that has it. It seems serviceable, but again, doesn't look like marble. Not sure her color, though, it is whitish.

The vanity I selected was special ordered from HD and looks like yours without the bottom drawers. I ordered it in cashmere grey like the one pictured. it is manufactured by Virtu America. Mine will only have a left mount sink so I need to special order that too. What did you end up with in terms of wall color and countertop? my flooring is 6x36 creamy white/light grey....the walls on the connecting bathroom are SW tony taupe. I was thinking sea salt for the walls...