Janet, I have seen a decrease in milk supply related to a mother drinking a large amount of water. I do not know how to define the exact amount of liquid an individual should consume. My general advice to mothers has been the old 'drink to thirst' stand-by and suggesting that they watch their urine. If it is a pale yellow, ok; if it is dark, drink more; if it is clear, they are drinking too much. I have had good luck with mothers using Mothers Milk Tea to increase supply. They are using 2 to 4 cups per day (usually, the 4). They seem to notice result in 24 to 36 hours. Hope this helps! Pardee Hinson, MPH, IBCLC Charlotte, NC [log in to unmask]