HI Marion, Usually there is well testing to make sure the water is drinkable. We know of a few under ground springs and the same rule applies. In NJ in most cases the Seller preforms the test prior to closing.
Our own house failed the test. we had a water purifier installed at sellers expense before we closed on our property.
FHA requires that your plumbing,heating,electric, roof and basement meet the guidelines. We should think that spring or well won't matter unless it not properly connected.
To be sure ask a mortgage representive, they will be able to provide the correct information for your state.
All the Very Best
Dave & Lisa