as stated earlier, the lack of solutes needed to produce even maximally dilute urine will cause a low urine output. the urine specific gravity will be low because of the effect of maximal dilution. the absence of solutes cause the urine to be hypoosmolar (less than 100 mOsmol/kg). the low urinary osmolality is rare and seen only with beer potomania, primary polydipsia, reset osmostat syndrome, or a very low dietary sodium intake.