You should give some details on the problems that you are having so it can be determined if you need a well or not. Is it a point well that you have now? Drilling a water well close to a roadway can lead to sodium problems but sometimes that is the only place where it can be drilled because of septic offsets.Having the pumping equipment int that tank with the moisture content can lead to problems. Your existing well only 40' from the septic might be a little shady. Have you had periodic water testing done to determine if you are getting any contamination?