Is it possible that water conservation is contributing to the water shortage?

Now that I have your attention, I realize that this probably sounds idiotic, but I was considering the fact that many people water their lawns at night. This was to decrease the amount of water evaporated by the sun, which is working I'm sure, but also decreasing the amount of water evaporated, condensed, and then precipitated. Just a curious thought that ran through my mind. No mean comments please, it was just something that I thought of.