The 5 gallons per day is WITHOUT showers. It is NOT being wasteful, nor is it being careful. This is a pretty accurate estimate after three years of summer cruising and NOT staying in marinas. I got quite a few off-line comments from other cruisers that are full time on their boats, and ALL of them said I was being conservative. I remember a weekend outing with a neighbor lady who came on our sailboat right after we got it. When we anchored for dinner, my mate went to fill a pot for potatoes, but there was no water. I checked everything, finally checking the tank. It was bone dry. I was sure it must have cracked. We headed home early. On the way home, the lady told us she had washed the dishes on the way down, and there was plenty of water. A bit of investigating revealed that she wasn't conservative in her operation! I'd always take an extra tank, if you have room!!!