They’ll, or at least they should chlorinate the well. It’s a simple safe simple process and is the standard appropriate method to correct the situation. My assumption is that the well water itself is probably not contaminated due to contamination that percolated down, but rather with this heat the well head itself probably just got some stuff growing in or on it. It should be sprayed with chlorine now and then. A dose of chlorine in the well and a spray down of the entire external assembly should solve it. I have a bad feeling though, that they won’t spend the money.. The form is required to be posted by law, yes, it definitely could be simpler..