Where is the water gym on diamond?
The water type gym is in pastoria city and the gym leader is Fen he has a: Gyarados male LvL 27 water-flying Quagsire male LvL 27 water-ground Floatzel male LvL 30 water hope i helped (:
For Pokemon Ruby/Sapphire/Emerald, the fourth gym is a fire gym. So, train a water type Pokemon by battling against the hikers at route 112. For Diamond/Pearl, the fourth gym is a water gym, thus train a grass or electric type Pokemon on route 212. For Platinium, the fourth gym is a fighting type gym, thus train a flying or psychic type at route 214 For the rest, i won't go on.
to cross water you have to go to celestic town (after defeating pastoria gym there will be a team galactic man follow him defeat him Cynthia will be there talk to her she will give you secretpotion use it on psyduck and you can go there) there will be an old lady in the ruins she will give you a HMSurf. After that defeat hearthhome gym and BINGO! you can use surf to cross water