I am now on my 2nd pair of Seal Skinz waterproof socks, I would't go backpacking in wet terrain without them. Before, I used to get permanently damp feet with the skin turning white and puffy. Now they stay dry and warm.
I wouldn't like to actually stand in a puddle in them, though. They've let me down on occasions, when I've planted a foot in water deep enough to go over the top of the sock. When that happens, the water gets inside the sock, which then won't dry, and it will smell of rotting cardboard.
Before Seal Skinz, I used to wear thin, wicking inner socks under thick loopstitch wool socks. Now I wear Seal Skinz under thin-to-medium loopstitch socks (they're designed to be worn next to the skin).
They're machine washable, at 40 degrees. Tip: turn them inside out for line drying otherwise they take days.