Altered water-electrolyte status resulting from chronic alcohol dependence has been reported, although the nature of any such derangement is controversial. To illuminate this problem, four groups of rats were exposed chronically to schedule-induced polydipsia conditions with a single fluid available: 5% ethanol, 0.9% NaCl solution of 5% ethanol, 0.9% NaCl solution, or distilled water. An ad lib control group was also used. The water-electrolyte status of these groups was evaluated in two ways. First, the diuretic response to hydrochlorothiazide doses (8-12 mg/kg) was measured after 3.5 months of chronic polydipsia. Second, after approximately two additional months of polydipsia, extracellular fluid volume, as well as plasma volume and electrolytes were measured. Both alcohol-intake groups drank approximately 11.5 g ethanol/kg/day over the course of the experiment. Urinary volume response to the diuretic agent did not reveal that chronic ethanol led to either water retention or dehydration, even when extra NaCl intake was imposed chronically (NaCl-EtoH group). Animals that were overdrinking either water or the 0.9% NaCl solution had extracellular fluid volumes that were greater than the NaCl-EtOH-polydipsic group, but they were not significantly larger than ad lib controls. There were no significant differences with respect to serum electrolyte concentration measures among the groups. In conclusion, animals that drank ethanol chronically in a pattern known to produce physical dependence revealed no altered water-electrolyte status when evaluated by acute responses to a diuretic agent, a chronically-imposed extra NaCl load, or body fluid compartment and electrolyte concentration measures.