Thanks to Saurav's question and Terry's answer I have solved the exact same problem of water leaking through the tank bolt (or at least it appeared so but I suspect the water made its way from the seal to the bolt perhaps). I too had the same porcelain bumps that while, small, were large enough to depress some of ridges of the seal joining the tank to the bowl. I also noticed a portion of the grey 'gunk' sealer used inside the tank was spilled over into the area the seal occupied and gummed up between the ridges of the seal. I grinded down the bits of porcelain and cleaned the gunk out of the seal and Voila! No leaks - finally after about 10 hours of frustration. Really glad I stumbled on this thread but not so glad about American Standard's qaulity control processes. I'd say this was poor. You'd simply need someone at the end of the line to inspect the tanks when they come off the mold and make what amounts to a 2 min fix. It frustrates me to no end when manufacturers tout the newest glaze, flush, environmental benefit or other feature but don't pay attention to the most basic and simple principle - qaulity. I opted to buy this model which was 2x more than a basic toilet only to wonder if this is indicative of what I can expect in the years ahead. I will be thinking twice about buying a new A/S model again. Let's hope the long-term experience with this toilet will make me keep an open mind.Thanks a lot for the reply. I took the flush valve off, and found 2 bumps in the porcelain under the flush valve's gasket. One of them landed right on the edge of the gasket, I could see part of it visible outside. So I spent some time with a dremel and various sanding wheels, and ground those down as best as I could. Put it back together again, and so far, no leaks (fingers crossed).