I have 4 1 gallon jugs from the supermarket, I don't have anything larger. If I did get something larger, I would have to go even farther to get the water. The fish are in the attic, and a 1 gallon jug is the largest thing I can fill in the 2nd floor bathroom sink. I would have to go down to the kitchen or the basement to fill anything larger. I can't have warm water because I often fill the containers before I actually do a water change, and my room is between 63 and 68 degrees. I can't get hot water from the tap because the pipes are rusted and I don't want to get that in the water. I could heat water in the microwave, but I can only do small amounts and again, that is 2 floors down from where the fish are. Usually what I do is use cold water from the sink but I only change about 2 or 3 gallons per week and when I pour new water in I make sure I don't just pour it in one spot.