Question: how many ounces of fluid should an 18 month old drink?
Answer: A: According to the Institute of Medicine's Dietary Reference Intakes for Electrolytes and Water, the Adequate Intake (AI) for water for children aged 1 to 3 is 1.3 liters per day; that's about 44 fluid ounces, or the equivalent of 5-1/2 8 ounce cups of water.