water

It's easy to forget that water is not inexhaustible when it flows so readily by the turn of the tap. Living on a boat certainly helps to develop a deeper connection to this precious resource. Depending on where you are, you'll have to treat it, catch it, carry it or pay for it.

In an emergency, the WHO recommends 10-15 liters a day per person(7.5L of which ought to be treated water), for washing, drinking, cooking, etc. A person needs between 2.5 and 3.5 liters of drinking water each day. At sea, being frugal is important, most boats do not having the carrying capacity for this amount of water. When we sailed for 52 days at sea between Japan and Canada, we left with 320 L of water, leaving us with 3 L per day per person. We didn't use all of it, we average 2.5 L per day per person, but only because we didn't do laundry, caught extra water underway, used a pressure sprayer to do the dishes, and because we bathed lightly. When anchored near a port, once a week, we would ferry four bins of 10 liters from shore to the boat. To conserve water, our sink faucet is operated with a foot pump, where each push draws out 60 ml of water, allowing us to measure our usage.

On passages, we carry extra Jerrycans of water, enough to sustain two people for a few more weeks than the length of our trip. Having separate bins makes for a more resilient system, if salt gets into one tank, it won't corrupt the entirety of your supplies. A sure way of preventing contamination, is to check all o-rings and tanks for leaks before leaving. We chose not to have a desalinator aboard Pino, and have managed well without it. It's a device that is expensive, high maintenance and power-hungry.

Our main water tank carries 170 L (45 US gal), our secondary has 50 L (13 US gal), while an additional 100 L (26 US gal) is stored in jerry cans.

In 2020, before the passage from Japan to Canada we replaced the holding tank with a water tank (see tank in below photo). We didn't have many options, but found a small water tank typically used in a lorry in Japan.

When it is not possible to dock at a marina, we use smaller(4x10L|4x2.6 US gallons) jerry cans to ferry water from shore. While it requires more trips, the lighter containers are less prone to breakage. When filling up, we filter the water.

Pino has no watermaker, and doesn't want one.

Treating water

The best method for distinfecting water is to boil it for 1 full minute(At elevations over 2,000 meters (6,500 feet) boil water for at least 2 minutes).

If boiling is not possible, it is necessary to filter the water prior to treating it with iodine or bleach.

Filter

Find a filter that is 1 micron absolute or smaller with a NSF/ANSI 42 or NSF/ANSI 53 certification. See all certified products.

On the boat, to filter our tank water, we hook a twin set of filter housings in the line to purify the water. The 1st stage filter is pleated, and removes sediment, silt, dirt, rust, and other particles, and the 2nd stage carbon filter reduce the content of chlorine, concentration of toxic heavy metals, natural organic matter and oil products. Then, we have a 6-cup Brita pitcher to filter the water coming out of the faucet. We do this because the tank isn't always 100% clean(it is damn hard to clean). A large Brita unit would be better, but we do not have the storage space for a 32-cup, and the 6-cup is short so it isn't likely to tip underway (easier to store than the taller pitcher, especially important because the lid doesn't clip on, it just rests there).

In a bind, if you can't get a good filter to remove debris/impurities, run the water through a coffee filter. We like to put a funnel over a large container, and to line it with a coffee filter. The filter will eventually get saturated (especially if the water is dirty), and the flow of water will slow down, it may be necessary to replace the filter.

For more low-tech options, check out this ceramic filter, or the 3 bucket water filtration system.

Household bleach(Sodium hypochlorite)

Chlorine is the most commonly used disinfectant in the world for treating drinking water(WHO, 1997) owing to its effective and efficient germicidal properties, ease of application, measurement, and control, persistence, and low cost. Note that bleach works best when added to warm water.

If the water is clear and of a temperature of 20˚C (68˚F), the suggested ratio of chlorine to water is...

• With 5.25% Sodium Hypochlorite: 2 drops(0.1 mL) bleach for 1 L.

Allow the treated water to stand for 30 minutes. If there is a lingering chlorine smell and the water looks clear, it is safe to drink, if not, add another 2 drops. Let the water stand for another 15 minutes

If the water is cloudy or if the temperature is colder than 10˚C (50˚F), double the above suggested ratios of chlorine drops to water.

Mix, and let it stand for 1 to 2 hours before drinking. The longer the treated water stands the better it works to disinfect the water. If after that time there is no chlorine smell, add 4 more drops and let it stand for an additional 1-2 hours. If there is a lingering chlorine smell and the water looks clear, it is safe to drink.

Things to remember:

• Use fresh liquid bleach (less than 1 year old).
• Use NSF-approved chlorine bleach products that is suitable for disinfection and sanitization(indicated on label).
• DO NOT use non-chlorine bleach that is scented, colour-safe, or that has added cleaners.
• Bleach doesn't remove chemical pollutants or disease-causing organisms (but in an emergency, if there is no way to boil it, it is better than nothing).
• Use a dropper for more precision when adding bleach.

To measure different ratios use this calculator.

It is possible to use purification tablets, but this may not be ideal if you need to treat a lot of water.

Iodine

Use liquid iodine(2%), or tablets, available in most drugstores. If using tablets, follow the directions on the package(usually 2 tablets per liter of water).

Liquid iodine works best with 20˚C (68˚F) water.

Treating water above 15˚C: add 5 drops(0.25 ml) of iodine to 1 L of water. Mix both together, and let it stand for 30 minutes before drinking.
Treating water between 5˚C and 15˚C: use the same ratios as warm water, but let it stand for 40 minutes before drinking.
Treating cloudy water: add 10 drops(0.5 ml) of iodine to 1 L of water and let it stand for the times listed previously for both cold and warm water.