It is certainly possible for well water to be a problem for plants, even if it's drinkable for us. If you have concerns, have a complete water analysis done. Be sure they test pH, alkalinity, total solids, etc.
Are you seeing symptoms on your plants that lead you to believe the water may be a problem? Do you have to use a filtration or softening system for the household water?
There were extensive discussions about this issue on IBC last year. Might be worth checking out. I think the bottom line is that water isn't often a problem, but it can be...especially if the source is a well.
Chris