The old rule of thumb was that if you had a drilled well, that water was safe from bacteria. It turns out this is rarely the case. The two most common bacteria that can be found in well water are E-coli and Coliform. If you have a well you should test for these two bacteria at least once per year. However, one should understand that all that test really tells you is that there were no bacteria in the sample water at the time of test. Installing a UV Sterilizer allows the water entering the home to be disinfected at the source to ensure you and your family are safe from unwanted pathogens. UV Sterilizer require yearly bulb and sleeve changes and cleaning to ensure they function properly.