http://www.reptileforums.com/care_sh...ter_dragon.htm
^Excellent water dragon care sheet^

A few exerpts...

Size: Adult males can reach up to three feet in length. Females are slightly smaller.

Enclosure: Young water dragons can start in a 10-gallon tank but will quickly outgrow this enclosure. Adult water dragons should be kept in an enclosure that is at least 4 feet by 3 feet. The larger the enclosure the better since too small of an enclosure can cause the water dragon to rub its snout until a bacterial infection occurs.



http://www.herphangout.com/caresheet.php?sheet=8

Another decent care sheet..

Max Length: 40 in.

40 gallon tank is minimum, adults will need 70+ gallon tank. Screen Lid required for air exchange. Large water bowl with airstone. Waterfall can be used to simulate natural environment.