WaterWar.net

Urban battles are rare in water warfare, and a very interesting, here is a run down of what I believe the best guns for these battles are

CPS 1500. Short enough for quick maneuvers, but has plenty of range for open areas
Vindicator K same as for 1500 but smallest setting becomes a riot blast has better field life but needs modding to do so
CPS 1000/1200/2100 K. Same as other k with Vindicator but less field life
Gorgon With the smallest setting turned into a riot blast this gun is hard to beat
Flash Flood/Article Blast. A riot blast makes this a deadly gun at close range

So that's my list, post your own list of top close quarters weapons

I'd still take my trusty 2000 or 2500, but fully realize that the length makes it more difficult to turn about quickly, as well as the fact that the pumping time required will make things quite difficult

For really tight quarters, I'd even take a PR pistol or two. Flash Flood is mainly good if you need the spread, but the riot blast is kind of a waste of water in almost any hit-based game.

In the end however, I'd find it very difficult to part with my 12k. The range, ease of tap shots, very little pumping per tap, etc. makes it my blaster of choice for urban, very CQB environments. It isn't too lengthy for getting around, either and I always extend my field life with water bottles anyway.