MOST well water should not contain bacteria and parasites. This is one comment that I may have over interpreted, but is egregiously incorrect. If a well is properly installed, there should only be clean groundwater entering the well after untold time and distance of filtration through the earth.
This second statement in response to my comments does not back up the previous statement, but it is much more accurate. RARELY these pathogens are present in well water, and they can be a serious risk to human health. Typically, unless there is a specific cause for concern, a well can be tested for total coliform bacteria, and assuming that result is negative, the worry over crypto/giardia isn't much worth your time spent worrying. On the other hand, coliform is easily introduced to water supplies from serious issues like surface water infiltration, or simple contamination due to improper sample handling. We live with coliform bacteria everyday, and it's very prevalence in the terrestrial environment is ubiquitous that it can be used as an indicator of other more serious issues.
I said I wasn't going to get involved, but here I am. Up to this point, I hope that I have not been offensive to anyone.
