I'm too lazy to count :P
There are 9 total. Azumarill,Blastoise,Empoleon,Kingdra,Milotic,Sharpedo,Slobro,Suicune, and Swampert.
Source: http://smogon.com/bw/tiers/uu
9 Pokemon in UU which are water. I counted. Source: Experience and I checked the same link as MF but he put it on first -_- Look at this.
LOOK HERE
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