how much to water

Ive been reading a lot and have learned quite a bit but im still not sure about how much and how often to water, all the way from seedlings to flowering. I would appreciate some info on this. My wife brought up something too that I havent thought about. She said that collecting water from an A/C unit off the condenser was good water to grow with, but I dont want to chance it. I have been using spring water.

stick your fingers in the dirt and feel if the soil is dry about 2-3 inches down. if it is, you need to water.

you can use the a/c unit water, but you might want to add calmag to it, b/c it probably doesn't have the minerals that are in spring water.

-p