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). 25/1 Filter: Replace Filter lubricate o ring sanitize housing and test water 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.