You never know what you're going to find until you find it.  In this case, a cute late-80s saltbox in Williamstown, VT sailed through the inspection until the water inspection. 

First, for personal and professional reasons, I always recommend getting a water test if the drinking water comes from a well.  That goes for buyer and seller.  It's not uncommon at all for there to be bacteria in the drinking water.  It can come from any number of places, (my favorite is the guy that said it came from "an earwig in the well".)  For all I know, that's exactly where it comes from.

In this case (the one in Williamstown, but I've also seen it happen in Berlin, Middlesex, Calais, and Barre--wherever people have wells), the owner has "shocked the system", and retested.  It's not an expensive treatment, and sometimes it has to happen more than once.  But it's all manageable.

The important part is that it's not a big deal.  As a seller in Montpelier or Williamstown, it helps to know this ahead of time, and treat.  As a buyer in Barre or Berlin, well, unless you don't care what you drink, you should probably get this tested.  The only potential inconvenience in the whole thing is that it takes a few days to do the test...so don't wait until a couple of days before the close.