Heylas--
I'm not sure how much other beardies drink-- I know some don't readily drink from a bowl or whatnot and so some people have to mist theirs which might make it seem like they "drink" less.
Kleio- my beardie- seems to act as you say yours does. She drinks when I put her in the bath, and she laps out of her water bowl and she also loves when I drop water on her head so she can lick it off.
Also did you check the basking temperatures, make sure they're not too high in the hot spots and cool enough in the cool spots and such...Does your beardie "gape" a lot? Mine was doing that when I had the tank set up at first (and after 2 days of trying to figure out why the heck it kept getting so warm, I was up at nite when the heat kicked on. *rolls eyes* The tank was right by a heating vent hehe.) After I resituated things, she stopped gaping)
Others on here will probably have better info for you, this is just my experience 
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0.2 cats (Pandora & Journey)
0.1 bearded dragon (Kleio)
0.0.1 green tree frog (Squishy)
0.0.1 goldfish (Namoli)