Ask Mr. Smarty Plants

The roots of a tree cover a space underground similar to the area covered by the crown of the tree.  Visualizing how your tree will look 10 or 20 years from now will suggest, I think, that the roots will be near the water well.  If these would just be small feeder roots there might not be a significant problem.  But if there is any leakage of water from the well area the tree roots will grow much more strongly in the direction of the well.  I do not know what kind of well you have and what the chances are that occasional leakages of water will occur in the future.  If there is any chance  the tree will sense that moisture is preferentially available at the well site you will be well advised to move the tree now, when it is relatively easy.

The Lady Bird Johnson Wildflower Center published a guide to tree planting.  Also, you can find many Internet web sites on tree transplanting, including this one.  It would be best to wait until winter when it is cooler and the chance of stress are reduced.  Try to avoid cutting the tree roots as you dig, making a circle around the tree at the drip line and digging deep enough to get under the root ball.   The soil around the transplanted tree should be kept moist for at least several months.  If you follow these guidelines there should be no trouble moving your young tree.