I have a 34oz water bottle that I drink 1.5-2 of a day, a couple 10oz cups of tea and a 12 oz coffee. Water and tea= about 80oz (on average) and then I have the coffee too. But since coffee is a diuretic, and I always put a little milk in it, I don't count it in my water consumption.
Probably between 80 and 100 oz a day. I can't keep water in my workspace, but during meals, work breaks, and at home, I'm usually constantly sipping water.
I try for a minimum of a gallon, though I don't always succeed. Anything less than that and I start noticing signs of dehydration in my body. More is better for me, but I don't always manage that, thanks to a small bladder and frequent pee urges, sigh.
I'm glad you posted this because this is an area I used to be so good at- I used to religiously drink 3 liters of water a day. Lately, even with tea and coffee (which count but not the same way water does) I probably get less than 2 liters. I'm a firm believer that dehydration- even mild dehydration- contributes to aches and pains, lack of energy, etc. I need to get back to drinking my water!