Abstract: A method for online condition-based monitoring (CBM) of a tank farm including a plurality of storage tanks includes providing a tank model including a diagnostic and/or predictive tank model based on calculated tank metrics that is derived from historical data including tank operation data. The calculated tank metrics include tank operational metrics based on the tank operational data for the storage tanks and tank condition metrics based on tank inspection or maintenance data for the storage tanks. The tank model provides relationships between the tank condition metrics and the tank operational metrics. Results are generated using the tank model including at least one failure indicia for at least a first of the storage tanks using the calculated tank metrics and current measured data for the first tank as inputs to the tank model. The failure indicia is processed for scheduling at least one maintenance task for the first tank.