A drilled well is almost always safe from biological contamination and is less affected by seasonal quantity and quality problems when compared to a dug well. Another aspect you need to consider is cost, and this is generally the same for a properly constructed dug well and a properly constructed drilled well. It’s also important to note that selling a home with a drilled well is a lot easier than selling a home with a dug well, and this is because dug wells often fail to meet certain bank standards, so they will refuse a mortgage as a result.