We made our own water in Mexico, using a reverse osmosis (RO) system. It’s like a very, very fine filter that filters the salt (and everything else) out of sea water. RO uses a lot of electrical energy, but if you plan for it, it’s not a big deal.
We met a few boats that filled their tanks periodically, which is also not a big deal. Water sources are about 120 miles apart, so plan accordingly. Obviously, those boats did a lot less washing than we did.
We also met and heard of way, way too many boats that got sick from bad water. Bad water is almost completely preventable. If you add chlorine to your water, you won’t get sick. If you don’t add chlorine, you’ll eventually get sick. Iodine doesn’t actually work — it’s not chemically active enough. Filters and UV treatments don’t work. UV won’t work where the light don’t shine, and filters only work until they get full (clog) or the filter gets changed without bleaching everything. Then they fail, and then you get really sick because all the contamination imbedded in the filter washes downstream.
So, first you need to clean (shock) your tanks. This is a highly speculative process, and it depends on how dirty your tanks are. If you keep your tanks clean, then you have less to do. We would add 2 cups of bleach to ten gallons of water at the beginning and end of each sailing season. Poor the mixture into (each) tank, bleed every faucet and hose bib until you smell chlorine, then leave it sit for at least 24 hours or until you return to the boat. Then run the system empty, add more water, and flush the system. Since our water tanks are clean, we left the tanks empty except for the bleach mix when we were away from the boat.
When you add water from a hose (from a roughly clean source), add one teaspoon of bleach per ten gallons of water, or one ounce of bleach per fifty gallons of water. If you’re adding water from a clear stream (in Desolation Sound, for instance) add twice that amount (note that the chlorine still won’t kill Giardia).
Since we knew our RO water was sanitary and safely handled, we added about half that dosage to our water tanks. The chlorine smell was almost always negligible. In addition, our RO system pumped into a smaller drinking water tank first, which we didn’t chlorinate except at the beginning and end of the cruise (or every five-six months of continuous cruising). You can also use a carbon filter to clean up your drinking water.
If you come into any kind of contact with people that have had digestive problems, wipe your boat interior down with bleach water (not a lot, but it should smell a little). Bleach water is also the best solution for mildew and mold, although vinegar works a little.
If you don’t want to deal with bleach bottles, or if you want to deal with something cooler than bleach bottles, then you need this—> The h2go purifier turns water and salt (or seawater) into a concentrated sterilizing solution that works like nothing else. It even kills giardia. And…solar power! That’s right. And…a flashlight. I can’t believe you haven’t bought one yet. Go buy one now!
People seem to be afraid of chlorine. They shouldn’t be. They should be afraid of cholera, shigella, legionella, giardia, campylobacter, norovirus, salmonella, cryptosporidium, et. al. Also, living full-time long-time on RO water has it’s own risk — mineral deficiency. A daily mineral tablet will do you no harm, and make sure the kids are using fluoride toothpaste. Their teeth will thank you.
Some older boats and RVs were plumbed with polybutylene (PB) pipe, which will fail when exposed to chlorine. It’s probably already failed. Make sure you use PEX when you re-plumb your boat.