These pants say they are gore-tex.... but...
These pants say they are gore-tex.... but the waterproof rating says they are 20K... isn't gore-tex guaranteed to be waterproof??
Yes, but "guaranteed" and 20K, might as well mean the same thing. Which basically means you can go swimming in them and the only way water is getting in, is through the holes where your boots are and from the top of the waist. Each company tends to do their own "standardized test", but 20k is supposed to mean, that they have to put 20,000 milimeters of water down a tube (or graduated cylinder, whatever) forcing it at the fabric, for it to go through, though every company uses a different sized tube and other such slight differences.
Long story short, you should still be good in torrential downpour, best thing next to a yellow gorton's fisherman suit.