Annual Maintenance: RO System Service Call: Service Technician will sanitize the systems, check pressure in the RO tank, replace filters and test water ( this will let us if the membrane is working to its optimum). UV light: Ultraviolet Light and lens replacement, test ballast, sanitize housing and test water pre filter​ replacement. Whole House Water Treament System. Service Technician will check stack, change injector and screen, will make sure the system is working at its optimal potential.