They are nocturnal so thats probably why you dont see him drinking during the day. But they usually just sit back and relax in the water bowl and drink it up like little dogs
i rarely see them drink, now and again when I feed them and replace the water I'll see them lap up a bit, but as others said they generally drink at night.
I've never seen our male drink. We've had him since January. The female I see drink all the time. I also see her lap up from the calcium dish, but not the male.