Assessing decongestive therapy delivered to a heart failure patient involves use of an implantable sensor configured to sense a physiologic parameter indicative of the patient's diuresis status and a processor coupled to the implantable sensor. The sensor may comprise a thoracic fluid sensor, a heart sounds sensor, a cardiac chamber or arterial pressure sensor, a respiration sensor, or a blood chemistry sensor, for example. The processor is configured to determine if a target level of patient diuresis has been achieved based on a relationship between the sensed physiologic parameter and a threshold developed for the patient, and to produce an output in response to determining that the target level of patient diuresis has been achieved. The processor may be disposed in an implantable housing, in a patient-external housing, or in a network server system.