All water treatment systems should be tested at least once per year to confirm the system is still working effectively. It is best to test both the raw/untreated water and the treated water. It's important to know what's coming in to compare with the treated water. Some treatment systems have two treatment tanks in series and for these systems there is often a tap between these two tanks that is an important place to test. If you are not sure where to test, you can email a photo of your treatment system for help figuring out where to collect water samples.
It is common to forget to test, so it is a good idea to ask us to send you a reminder once per year. There is no cost to set up a water sampling reminder. Email me at email@example.com with your contaminant(s) of concern and I will get back to you with recommendations for the most appropriate test and what it will cost.