Virtual reductant level sensor

An aftertreatment system comprises a reductant storage tank and a SCR system fluidly coupled thereto. A reductant physical level sensor and a tank temperature sensor are operatively coupled to the reductant storage tank. A controller is communicatively coupled with each of the sensors and configured to: interpret a first level output value from the physical level sensor and a first temperature output value from the tank temperature sensor. If the first level output value is below a first threshold, the controller determines if the first temperature output value is below a second threshold. If the first level output value is below the first threshold and the first temperature output value is below the second threshold, the controller determines a virtual reductant level in the reductant storage tank and indicates the virtual reductant level in lieu of a physical reductant level in the reductant storage tank to a user.