Because pumping water is so much more FPS-friendly, the water's always available, and the whole pump system fits right into every fort layout!
/sarcasm
I move a fair amount of water around--not always pumping, but lots and lots of mist.
In Whiteletter, I built an artificial river that dumps water out of about 20 aquifer tiles into a 5-wide channel about 200 tiles long, pouring down through my dining room and into the cavern 15 z levels down. The cavern lake now has all these little 1s floating around the surface, a whole lot of them. It's really kind of neat to look at. They're constantly dancing around, trying to find the edge of the map so they can flow off. This whole arrangement made
no dent in my FPS. It was capped at 100.
Later on, digging and immigration had brought me down to 85 FPS. Then I excavated down staircases on an (approximately) 35x35 area right over the edge of the aquifer, so I could see exactly where it was (so I could build a power generator for my magma pump stack). When yellow and teal cave moss grew on it, it was so horrible to look at that I floored over it. My dwarves were doing basically nothing else. As they built it, the game ran slower and slower. My FPS went from 85 to
40. I deconstructed the floor and the FPS went back up to 80 or so.
Except now the floor was yellow and teal down staircases that had rocks on them, so they were
blinking.By the way, when I got that 45 z level magma pump stack running? No hit to FPS there either. (I was using the improved temperature-controlled magma stack someone came up with this year.)