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Environment Canada estimates the distribution of domestic consumption as shown in Fig[http://www. 11-1ec.Fig 11gc.ca/eau-1 Distribution of domestic water consumption© / Environment Canada http] estimates daily per capita usage as 79 gals. <ref>https://www.ec.gc.ca/water/imagesindicateurs-indicators/manage/effic/a6f7edefault.htmasp?lang=en&n=7E808512-1</ref>
→Calculating Water Capacity
= Water Capacity =
Standard estimates of water consumption for yachtsmen yachters assume a certain austere lifestyle. But everyone’s comfort level is different.
== Design Considerations ==
There are many estimates of water consumption available for yachtsmenyachters. But it is better to start with first principles when designing your system. If your boay is intended as a live-aboard in all seasons, while remaining qualified as a passagemaker, getting the heating, air conditioning and water systems right-sized is critical from a comfort and energy-efficiency aspect.
In the water system, this comes down to how much hot water do we need in a day. We don’t need that much for drinking and cooking. The difference is in life-style usage. Everyone’s comfort level will be different. The criteria for a live-aboard are different from a weekend cruiser or racing yacht. Living aboard, we should always have hot water when we need it; not waste water; and conserve energy.
Other yachting estimates are as high as 15 gal a day per person. At the other extreme, one 400-passenger cruise ship, the <i>MV Millennium Queen</i> (believed broken up in 2001), budgeted 60 gal per day per passenger, which is close to domestic consumption. Domestic consumption is a benchmark for a live-aboard, but estimates still vary widely.
For a standard office, guidelines are 25 gal/day per person but have been shown to be as low as 6.8 with conservation measures [3]<ref>http://ncprojectgreen.com/</ref>. Of course, office estimates don’t include cooking, showering and washing clothes, etc.
For domestic consumption, [http://www.watertechonline.com/ WaterTech.Online ] also recommends 25 gal/day d per person [4] but [http://www.nrcan.gc.ca/ Natural Resources Canada ] (NRCan) estimates real usage as 88 gal/day [48]d.
NRCan says average daily consumption is 1000 Ll/day d (264 galsgal) for three people with 40% for toilets. This puts Canadians among the thirstiest on the planet. Must be all the Beer! More Beer! My toilet flushes with 1.6 gal so NRCan assumes I hit it 22 times a day, or about every 45 min. Putting aside the toilet jibe, I find 88 gal realistic, as shown later.
Vendor specifications also indicate that many marine toilets require 3-5 gal per flush, with the most efficient (VacuFlush) requiring only 0.375 10 gal (/0.8 L)39 liter. <ref>http://www.dometic.com/USA/MS-11346-Marine/PG-11395-Toilet-Systems#q2</ref> The more profligate ones can use seawater but VacuFlush requires fresh water [49].
Other sources estimate that domestic hot-water consumption alone runs 20-35 gal/day per person, with a peak demand of 10 gal [?]. To meet such a peak demand, the [[HotWaterHeater|hot water heater]] must deliver 10 gal/person at any time. Additional capacity is needed for appliances, such as dishwashers.
Other capacity recommendations for hot water tanks range from 7 gal per person [2] to as high as 17 gal.
In tests in my apartment taking showers not baths I the observed a daily consumption of was about 40 gal. Taking a bath (52-in bath) quickly jacked the number up into the NRCan realm. These are the results of the tests:
* Bathing
* Dish washing 4 gal/d (4 @ 1 gal)
* Laundry 2 gal/d (pro-rated from 14 gal/week)
* Hand washing 2 gal/d (4 @ o0.5 gal)
* Drinking 1 gal/d (mostly Twinings Earl Grey tea)
* Cooking 0.25 gal/d
* Household cleansing 0.25 gal/d
The drinking consumption might surprise you. For years -- [http://www.onemedical.com/blog/live-well/daily-water-intake/ well, since 1945!] -- the health community has been erroneously fixated on eight 8-ounce glasses of pure water per day. The [http://iom.nationalacademies.org/ Institute of Medicine], which was responsible for the 1945 study, now liberally recommends a total daily water intake of 3.7 liters (0.97 gal), from all sources including water, wine, beer, coffee, tea, soda. == Reduce Consumption == Water consumption can be reduced using (descending order) water-efficient shower heads, toilets, dishwashers, clothes washers, and automatically closing taps. Low-flow shower heads alone can reduce water usage by 30%. Older shower heads deliver 4 to 5 gallons (15.1 to 18.9 litres) of water per minute. However, the The [http://www3.epa.gov/ USA Energy Policy Act of 1992 Environmental Protetion] Agency <i>WaterSense</i> lavatory faucet specification sets the maximum water flow rates rate of lavatory faucets and faucet accessories at 21.5 gallons (9.5 litres) per minute (gpm) tested at a standard residential water flowing pressure of 80 60 pounds per square inch (552 kilopascalspsi)(common water pressure in most households).<ref>http://www3.epa.gov/watersense/pubs/faq_bs.html</ref>
== Tank Overflow ==
== Conclusion ==
Before doing the above test, I had settled on 25 gal/person/day as a design goal. Afterwards, and because water capacity is so critical for a live-aboard, I increased this to 60 gal/person per day overall. With a 250-gal water tank, this gives a base cruising capacity of two days for two people. A 500-gal tank would provide the same for four people. A [[Watermakers|watermaker ]] would have to supplement this for extended cruises. [[Category:FreshwaterSystems]]