We have 75 gal on our h37.5
We estimate about 2 gal per day per person, and that includes water for everything. So 75 gal should last 1 person 37 days, or 2 people 19 days. Now, that being said, I would love to have more water too.We have thought about adding another tank, but we really haven't found a good place for it. Maybe under the cabin soles below the seats or in the bilge. But the bilge is already taken up to store other things, and under the cabin soles would be a heck of a lot of work, mostly for me. I am the slave on our boat. Most of the places we cruise, there are marinas for us to tank up every few days, so it is not too much of a problem. We only have to watch our water usage when we are way way up north in Canada, or out out in the pacific, which is not too often.So, we have decided to stay with sun-showers. A 5 gal bag could stretch into 4 quick showers. Now, if we are in some bay with warm water, we jump in, get wet, get out, soap up, jump in again, get soap off, get out, rinse with fresh water, we could get 8 showers out of a 5 gal bag, along with 2 screams *yks per person per shower. Obviously we don't do that too often. Here in the Northwet, the water is a bit brrrrrr.I would also love to hear what others have done to increase water supply, not including water maker, too much trouble unless we are ready to stay out out there.