How far (distance) should I expect my neighbors water well drilling to effect MY water well?
Depending on the depth of his well. If is close to the same depth as yours you will be taping the same aquifer or water supply. These aquifers (below ground pools of water) sometimes have a directional flow. If you are on the downward flow side you may notice some discoloring from the disturbed pool of water. What is more important is that his new well stay 200 feet or so away from his and your septic fields. I assume you are on septic systems if you do not have city water? There is usually a county code saying how far from a septic the well must be. I would imagine your well supply has plenty of water for another user, since he had a well already and is just drilling a new one.