I too thought of the backpacking filter. Good one's will filter just about everything including viruses and bacteria. Check out youtube where they filter a muddy puddle and drink it! But, they are slow and would be way too much hassle for me to fill gallon jugs. I've used the UV light pens (Steripen or Starlight) on land based trips to fill 16 oz. bottles and it's great for two people. I don't quite get the arguments for boats with water makers. For shower and dishes yes! For drinking? I wouldn't. You are still drinking from the tank. You have no idea what previous charters did. How many times do you read trip reports where the water maker broke and the charter company said just fill the tanks at any given marina and keep the receipt for reimbursement? Same thing with UV lights or reverse osmosis filters. You are relying on the charter company to make sure they were changed on a timely schedule. Good luck with that! UV lights have to be VERY clean to be effective and drastically lose effectiveness as the bulb nears the end of it's lifespan. I'm on well water at home and have a whole little room dedicated to filters! And I still drink bottled water most of the time.