Spring water is NOT an indicator of good drinking water or good brewing water. There are plenty of springs that are not suitable for drinking. I'm assuming that this is a shallow spring that is seeping from the ground. They are the most susceptible to contamination from biologic and chemical contaminants. A deep well that is flowing could be safer, but even that is not a guarantee.
Give the water a sniff test first, then a taste test if you dare. If it tastes good and doesn't have metallic flavors, then I would send it off to a lab to determine its major ions with respect to brewing suitability. You'll still be in the dark with respect to chemical contaminants unless you pony up big bucks for testing.
Since I have an extensive history in water supply and groundwater, I am less amorous for unknown water supplies. Better safe than sorry. Unfortunately with chemical contamination, low levels that are not acutely poisonous (kills you immediately) can still produce a chronic toxicity that may eventually kill you if you drink enough of it.
Spring water is NOT a guarantee of good water.
Martin Brungard
Carmel, IN