Disinfection is only used when a new well is drilled, flooding occurs, after a well is serviced, if harmful bacterias are found, and if the well has been sitting without use for an extended period of time. WSC recommends that you have a licensed well contractor make any repairs to your well and disinfect it afterwards. You can also disinfect your well, but before you do, you should read the wellcare® information Sheet, Disinfecting Your Well.