1/4" gap is pretty large. My undermount measures about 1/8".

Have you looked under the sink to see how it's mounted? Did they use only adhesive or wood&clamps? Definitely call the person that installed it!

I, too, would call the person that installed the sink. In our case, it would be the granite installers. My caulk link on my ss sink, and it's a heavy single basin 16 gauge Franke, has about 1/8" clear, silicone caulk line, too.

FWIW, my Fisher and Paykel DW was leaking ever so slowly under my floors. Acutally, it was leaking on each of the pans and running over and under the DW. After much ado and many visits, F & P replaced my dishwasher because over time it had warped the plastic. Also, they said my dishes were too large and sent me a different interior dish holder that holds my 10 1/4" dishes at a steeper angle so the dishes won't get in the way of the drawer closing. I don't think this was the problem, but whatever. I still got a new dishwasher.

My point: you might want someone to check out your dishwasher, too, for a slow leak if your wood floors are cupping. This is exactly how I found my dishwasher leak: wood floors cupping.

Thank you Annz and Sherrilyn. Yes, it was the granite installers who set the sink. I should have known....

Supposedly the granite installers are "one of the best" according to our gc, as well as our neighbor, who used a different gc than us, and our plumber. But this "one of the best" granite installer screwed up our original granite installation by mistemplating and/or mis-cutting one counter top so that it was about 2 inches too short on one end. The end result was a month's delay and we had to go out and pick NEW granite slabs because our original ones were one of a kind and unavailable to match the rest of the install that was okay. So I didn't end up with the granite that I loved (what I have is okay, but I don't love it) and now I'm afraid my sink is slipping. I have heard through someone else that this GC is no longer using this granite installer. Hmmm...

So far the GC has not returned our call, but tomorrow my husband will make a more "urgent" one. I have a pit in my stomach about this because I don't know if once an undermount sink is already in, if it can be adjusted. I looked underneath and it looks like it is clamped onto the plywood subtop.

Sherilyn, the floor in front of the dishwasher looks okay, but you have a good point in that our floors are not level so water could run underneath and pool at the sink. That is what has happened with this sink leak where the water pooled in the cabinet and then ran down the back and forward. The damage is actually not right in front of the sink, but a little to the right.

I suppose I will have to call the floor guy, although my husband said the floor may flatten down a bit once it's dried. I am skeptical about that.

Once the humidity levels out in the wood, your floors may straighten out. It is possible. My laundry room has porcelain tile and there is wood flooring leading up to the door to the Laundry. One night, but eldest son washed clothes and went to bed. When I awoke the next morning, my carpeting in my BR and closet was soaked, as was the entire hall wood floors. My Brazillian Cherry hardwood floors cupped hideously. I literally took my rainbow vacuum to the floors and sucked out water from the cracks and got a heated dryer and fans in those areas for almost a week. Eventually, those floors laid back down. It took a couple of months, but you can't even tell right now.

F & P offered to redo my floors, but they laid back down, so I passed on it.

As for replacing your undermount sink, yes, of course you can. They can take a knife or razor blade to the caulk and cut it away. I would just want to make sure that they were very careful about prying stress points should they think they have to put a screwdriver underneath the sink to redo the caulk. It will most likely work out fine. It's obvious that the install may have been a little sloppy. The granite company should help you out here.