Well owners are strongly encouraged to test their well water annually for pathogenic bacteria and nitrates. Here is an article that brings home the reason for sticking to this schedule: Well Water Found to Contain Nitrates.
Nitrates can be found in potable water from several sources. The most common are nitrogen-containing fertilizers, leachate from septic systems, or runoff from agricultural activity. Nitrates are mainly a health concern for infants under the age of two.
Treatment: Nitrates can be removed by reverse osmosis or by an ion-exchange resin specific for nitrate removal. An ion-exchange resin functions much like a water softener.
We’ve put together an information video to help well owners learn more about the why and how behind well chlorination. We did this because when we talk to most well owners, we find they don’t really understand what’s the right way to sanitize their well. Here’s the link: Well Chlorination