Pre flowers are a genetic trait of the particular seeds you planted and are not caused by any sort of water.
Any water fit for human consumption is fine for cannabis. I use tap water and have never in 35+ years ever bothered with adding chemicals unnecessarily.
I guess my forum name indicates this!
Using expensive bought water will not magically transform plants into producing "super buds"!
"Super buds" need great lighting first, good root room, good nutrition, good air exchange and moderate watering.
Springwater can be overly salty and is not ideal for cannabis.
Hope this helps, Organoman.