Water Supply for Off-Grid Container Houses

water-container-home-living

Over millennia, all our ancestors had been living in off-grid environment, but not many of us would like to move back to times when fireplace was the only source of available energy and water supply was remote. Fortunately, the enormous technological progress observed over the last 50 years made it possible to generate enough electrical energy in almost any off-grid location. Thanks to solar panels, wind or hydro energy, we can create comfortable off-grid living conditions meeting standards of the 21st century.

Off-grid-container-home-watter-supply
Unfortunately, the access to the most important “ingredient of life” – fresh water, is much more limited. Accustomed to unrestricted access to “tap-water” coming seemingly out of nowhere, we simply lost touch with the fact that fresh water became one of the scarcest resources in the world. While we can harvest the energy almost everywhere, it does not apply to fresh water as it is quite unevenly distributed across the land. That’s why not every off-grid location may guarantee conditions for life as we expect it these days. Having said that, it doesn’t mean that we are completely powerless in this matter, but rather that we must carefully plan our off-grid life. As the first step, we have to find answers to the following questions:

a) What is the minimum amount of water that will meet our daily personal requirements?
b) How much we can afford to pay for the access to water?
c) Can we tolerate discontinuities of water supply and if yes, then for how long?

Of these, we have some control over the first two, but with the last one, we are fully at the mercy of Mother Nature.

1. Daily use of water

Statistic shows that American families use on average 300 gallons of water per day per household (about 210 gallons for interior use and 90 gallons for outdoor). European statistics show more modest daily numbers – about 120 gallons of water per household (assumed all for interior use).
We will add here one more number, pointing to the level of our lavishness but also giving us a better sense of what may be the reasonable limit (numbers for a family of four):
a) It is estimated that only 40 gallons (150 liters) of water per household per day is needed for basic human needs (while keeping some level of comfort).
b) With conservative approach this number can be lowered to sort of absolute minimum of about 25 gallons (95 liters) per day.

Given such wide differences between the estimated value of required amount of water and its real consumption let’s see how the water is used per household or in other words, where the “taps” are open “too generously” and for “too long”. Identifying largest “drains” will help us to better manage water resources at an off-grid location.

Daily usage off grid water

End uses of water for households in the U.S. in gallons per household per day and percent of indoor use. Author: Benedykt Dziegielewski, Source: Wikipedia
And another analysis, this time also including outdoor use (lawns, washing car, driveway etc…)

W@ater Usage houshold US

Where the water goes in an average US household. Source: Analysis by Benjamin D. Inskeep and Shahzeen Z. Attari published in the Environment Magazine July-August 2014

Both diagrams clearly show that the biggest “water holes” are Toilet, Shower, Laundry (Washer), Faucets (kitchen and bath) and Leaks (if we put aside for a moment the outdoor).
The pictures may be quite discouraging, but as you will later see (subject of another article), by using newer, water-efficient appliances (marked by WaterSense label), changing wasteful habits and being committed (what may be the hardest to do), you will be able to bring the use of water to a reasonable number of gallons per day.

Sources of the freshwater

The degree of difficulty related to the access to freshwater largely depends on the location of your off-grid container house. Nearby spring, creek, lake or source of groundwater will offer almost continuous access to the water although in exchange. In practice however, it may be more difficult to find such premium locations. Fortunately, “rainy” climate zones open much larger areas for possible locations of off-grid container houses. But rain has its own limitation – it’s seasonal character and so necessity to store large amounts of water to get through dry seasons. Obviously, dry zones with low yearly rainfall rate will make any access to freshwater challenging and costly.

1. Rainwater

Since long most of us realized that in this world, nothing is free. Well, there are still some exceptions and one of them is Free Water falling from the sky. Understandably, since the beginning of time we were taking it for granted wrongfully assuming that the only gift that ever fell from the sky was the Biblical Manna. These days it is clear that we couldn’t be more wrong. Now more seriously – availability of rainwater is the true blessing, not only because it is free, but also because it has potential to be the cleanest source of water on Earth.
Rainwater collection is probably the most popular method of harvesting freshwater in off-grid locations and certainly least expensive one. However, at least two conditions must be met to make sure that the rainwater is a viable solution, and these are:

a) Average yearly rainfall and its seasonal distribution makes it practical
b) There are no sources of heavy air pollution in the area of your location

USA-precipitation-map

US Annual Precipitation Map (Source: ElDoradoWeather.com)
Average Annual Rainfall (Precipitation)

Your location must receive a decent amount of rain per square meter (square feet) over the year. Usually, the rainwater is collected from the roof of the container’s house and directed to tanks by gutters.
Now comes the math:
The local weather pattern is a cyclical phenomenon statistically described over the length of the year. Based on the available data from NOAA (National Oceanic and Atmospheric Administration) you must calculate how much of water can be “statistically” collected by the surface of 1 square meter (1 square foot) over the full year.
Knowing your daily water needs, you may calculate the amount of water needed by your household over one year. For example, assuming 40 gallons of water per day you will find the minimum yearly consumption to be 14,600 gallons.
Knowing the average rainfall (precipitation) at the given geographical location (in countries using imperial units it will be expressed in linear inches per 1 square inch of surface) you can calculate the minimum surface of roof to harvest the required amount of water. For example, at the location with an annual rainfall of 45 inches you will need the 520 sq. feet roof.
Roof area = (14,600 x 231)/(45 x 144) where 45 inches is the rainfall, 144 represents the surface of 1 sq. feet expressed in square inches and 231 is conversion to gallons (1 gallon = 231 cubic inches).

Unfortunately, the average rainfall represents only statistical value measured over the last 30 years. Given weather anomalies (in this case possible lower precipitations) the rain-collecting area must be larger than calculated minimum of 520 sq. ft. Good news is that it’s still realistic solution. Note that two horizontally configured 40ft containers (or four 20ft units) have the combined footprint of 640 square feet what also offers 24% “safety” margin for lower than average precipitations. However, in areas with precipitation of 22.5 inches you will have to double the surface of the rain-collecting area (in this case add an extra roof).

rainwater-tanks-for-container-homes-off-grid.

Annual Rainfall Distribution

Rain is not the continuous phenomenon, so you will have to provide a means to store rainwater harvested during rainy periods for the use over the following days (possibly weeks and even months) of dry weather. Calculation of required storage capacity (tanks) is based on statistical weather patterns. The bottom line – you have to store water for the longest possible dry period at your location based on local data from NOAA. As above, you will have to also add extra capacity as the “safety margin” for weather anomalies. For example, assuming the dry period of 6 months and mentioned above water needs of 40 gallons per day, the storage must be able to collect a minimum 7,300 gallons of rainwater to meet your household needs.

Well, this is just an example giving you the picture of what you will face when deciding to use rain as the main source of water in your off-grid location. Also note that the numbers above are quite conservative because many of you will probably appreciate higher volume of water for daily use (here it was assumed only 40 gallons/day) or extra water for outdoor needs (gardening) etc. BTW- the good news is that at least during the wet season you may have a much bigger amount of water available for daily use.

Air Pollution

Raindrops form by condensation of vapor in the upper atmosphere. Given that fact that the vapor is the cleanest form of H2O, rain could be considered as a sort of naturally distilled water (also for free). While theoretically it is true, practically due to almost omnipresent pollution of atmosphere by industrial-era gases and microscopic particles, raindrops reaching the ground level are more or less contaminated.

If you add to that dust, birds drops and insects’ contribution accumulated on roofs, it is clear that the rainwater must be purified to meet relevant standards for household use. To cut the cost, you may use two different distribution systems, one just filtered for toilet, washing machine, gardening, feeding animals etc… and another one purified, strictly for drinking (cooking, dishwasher, teeth brushing etc).

Note that practical and affordable home Water Purification Systems will remove particles, heavy metals, minerals, will neutralize microorganisms (if any), however they will be inefficient when it comes to elimination of chemical components absorbed by rain (or vapor) from the atmosphere. For example, Sulphur (S) or Chlorine (CL) in contact with water will form acids, while exhaust gases (near busy highways) and chemical plants may contribute to even more complex substances making the rainwater unusable for consumption! (more on that later). That’s why an initial evaluation of the environment at your location is crucial!

Notes:

a) Make sure that rainwater collecting surface does not contaminate the water by leaching their own chemicals. Metal (typical for container houses) or clay tiles roofs are safe solutions, while asphalt-based roofs (including popular shingles) or treated wood are not suggested for rainwater collection.
b) Keep your water-collecting surfaces (roofs) out of trees as these are favorite “meeting places” for birds, and then “things” happen.
c) Water stored in tanks for longer periods of time becomes stagnant. Lack of freshwater inflow will create favorable breeding conditions for microorganisms. That’s why water tanks must be periodically cleaned inside from all signs of life!

2. Nearby creek or lake

Location next to creek or lake may greatly help to solve the problem of water for your off-grid container house. The only real issue will be getting relevant permissions from local authorities and EPA (Environmental Protection Agency) what may be a “task” on its own, especially if the water does not run through (or belong to) your property. You will have to order initial tests confirming that the water meets applicable standards, but even when positively tested, you will still need a residential water purification system. It’s because the surface water (creeks, streams and lakes) is exposed to external sources of contamination and so at any given time the quality of water may go below expected standards. The risk will be quite high if your house is located in an inhabited, agricultural or industrial area.

Note that we did not mention here rivers as potential sources of water because they will certainly be polluted if not by industry or residential communities, then for sure by agricultural activities. Purifying such water is a serious task!

Creek for off grid water

Mountain creek in protected areas may be used as a source of clean water (purification will be needed for drinking water).

The main questions you have to answer before committing to “wild” water source are:

  • a) Is the water source (creek, stream) available over the whole year? In other words:
    can it vanish during dry seasons living you at the mercy of water hauling companies?
    can its water level drop so low that diverting it for residential use may endanger downstream environment (what means that EPA may prohibit its use)!
  • b) Does the water source freeze over the winter?
    While running water has major advantage over sources of stagnant water, the only way to minimize the impact of freezing temperatures is to store the water for the future use. In other words, to install the storage system (tank), capable to collect enough water to get you through the critical period of winter.
  • c) Is this a source of running (creek) or stagnant (lake) water?
    While the sizable lake will act as a virtually unlimited source of water, as quasi-stagnant, it will be breeding space for microorganisms and prone to pollution (especially if not protected from human activities). As the result, lake water will need more efficient (and costly) water purification systems.

Note that thanks to locally available solar or wind energy, the source of water does not need to run through your property or even be near it. Solar pumps will do the job!

Dankoff-Solar-Power-Water-Pump-

Dankoff 3040-24pv 24Vdc Direct Solar Force Piston Pump. It’s quite noisy, but runs directly on DC power and compared to AC centrifuge-based pumps, it does not have any significant surge current.

3. Groundwater sources

Shallow waters

In not that remote past, wells (especially in rural communities) were commonly used as sources of freshwater. Mostly shallow, built by digging a wide hole to reach water table at depths less than 25 feet from the surface, for centuries they aptly served rural populations.
These days dug wells are almost completely replaced by municipal water systems. But it’s not the only reason that that they lost their battle with modernity. It also happened because of poor quality of shallow underground waters or even their seasonal disappearance. Obviously, in the face of heavy industrial and agricultural pollution, filtering capabilities of shallow layers of soil, sand and stone seem to not be up to task to guarantee required quality of water. What makes it worse, traditional dug wells are not cased continuously so they are prone to also gather almost unfiltered but often heavily polluted runoff waters.

Manual-pump-Paul-Sablema
These days the traditional manual water pump is rather the charming relict of the past (Source: Paul Sableman / Flickr (Creative Commons)).

While traditional shallow wells still keep their charm, the whole concept of using shallow waters for needs of modern household is rather obsolete. Well, to be correct, thanks to relatively low cost, shallow water wells can be used as secondary water systems for toilets, lawns, car washing, feeding animals, gardenin etc… However, given the fact that shallow waters are available mostly in rainy climate zones, it may be more economical and healthier to simply capture more rainwater instead of digging the shallow well.

Deep waters

Deep residential wells are built by drilling and driving pipes (usually 6 inches wide) into the ground that can go hundreds of feet down through multilayered structures of soil, sand, sediments and stone. For this reason, they are known as Driven Wells.

Deep underground water, due to much more efficient natural filtration process is usually free from omnipresent surface pollution. Often you will not need any extra filtering system (if any, then eventually filters removing minerals like calcium or magnesium). Deep underground water sources are also almost independent of weather patterns and droughts observed at the surface. They represent almost unlimited sources of ready to use water.
While initially more expensive, thanks to modern drilling equipment it is a very effective method of getting access to fresh water and an ideal solution for off-grid container-based house.

Note that in shallow water wells, pumps are usually located on the surface (house’s basement or an exterior booth) so they are easily accessible when needed. In contrast, deep, driven-well pumps are located deep underground, submerged in the water. That makes them difficult to access in the case of failure.

These days drilling a deep-water well is a straightforward process (Source: Drill My Borewell, Bangalore, India)


 Concept of deep-water table (Source: Process of completing a well, by Quy Nhon Phan Nguyen)

Well, nothing is perfect in this world, no wonder then that there are also serious limitations to potential benefits of underground water sources. They are imposed by:

a) Nearby open-pit mining activities.
They may quickly drain underground reservoirs of fresh water (certainly those containing water at depths attractive for residential wells)
b) Fracking business
During the fracking process, huge amounts of water mixed with various chemicals is injected under high pressure deep into the underground layers of sediments with the goal to crack them and release the trapped gas. While gas finds its way to the surface where it is captured, toxic water stays underground heavily polluting deep, underground aquifers. The final effect – the otherwise pristine, drinking water becomes totally unsuitable for any household use.

4. Springs

 

Living next to a mountain creek is a blessing, hoverer living next to the natural spring should be considered as winning a Lottery Ticket.

Natural springs are characteristic for mountainous regions where waters continuously flow under the ground protected from the exposure to eventual pollution on the surface. Additionally, mountains are not preferred areas for major agricultural activities and animal farms, so they are mostly free from pesticides, fertilizers as well massive amounts of animal waste.

Flowing water (in contrast to stagnant aquifers) is undergoing continuous natural purification process that’s why when it emerges from the ground, it usually represents the source of the healthiest water on Earth. Healthiest does not mean that it is the purest water, because often it includes many minerals like calcium, magnesium or potassium (depending on the chemical composition of sediments that acted as natural filters). These are mostly healthy minerals but if their concentration is too high, they can be easily filtered by commercial Water Filtering Systems. Note that, flowing, underground waters are not exposed to organic life, and so are usually free of potentially toxic microorganisms.

water-spring-for-container-homes-off-grid.

Fuente de los Baños (Spain)

Bottom line: – if you can get relevant permission(s) from the local administration, the nearby spring is a gift from the heavens in the form of source of free, drinking-quality water.

Harnessing spring water may require some work, because you should not expect it to emerge from the ground in your basement. But the initial investment will quickly pay-off thanks to minimum filtering effort and most likely very good quality of water.

First you will have to protect spring’s water from contamination by surface waters and animals. It will require to harness spring’s water right at its source into protected concrete tank. From there you can divert water to your own distribution and storage system using either the force of gravitation (if possible) or a solar pump.
Note that adequate storage tank(s) is mandatory part of the spring water system, because in majority of springs the water flow highly depends on the weather (season of the year).

5. Unconventional Sources of Water

a) Atmospheric Water Generator (AWG)

It’s an unlikely solution so we mention is here just for completeness of the subject. Technically. easy to implement because it is based on the condensation of moisture on cold elements of commercially available heat exchangers. Typical example is a familiar A/C unit where the “byproduct” of the cooling process is the water extracted from the moisture contained in the air (typically wasted into sewer or soil). Unfortunately, such system designed solely for the purpose of harvesting water from the air requires a lot of energy and technically can be justified only if you generate too much of solar or wind power. However, if by chance you will have an A/C system at your off-grid location, you should consider collecting water for household use.
Similar effect is produced by refrigerator (collected water is naturally evaporated into air) or dehumidifier (from time to time you must empty its water tank).

b) Fine Mesh

Another version, but this time of passive humidity-capturing element is a fine mesh (in this case “passive” means that you do not need any extra energy for that process). Mesh can capture invisible microscopic fog droplets from passing through it air. Once merged into larger drops, water will drip down the net into a water collector. For this reason, such systems are often called “Fog Catchers”.

The “beauty” of the fine mesh is that it can be easily (and at low cost) deployed in large-scale systems. You will be surprised to learn that mesh-based Fog Catchers are successfully used in the Sahara and Atacama Desert (the latter is known as the driest place on Earth).

Just to give you some idea, such system spanning 600 square meters (about 6,000 square feet) deployed in dry, mountainous area of Morocco provides few thousand liters of drinking water per day to about 500 inhabitants of local villages.

To “demystify” a bit the idea, let’s mention that the Moroccan Fog Catcher is deployed in very specific area where moist pushed by the wind from the sea is trapped between mountains. That makes it an ideal place for harvesting water.

Mesh-based Fog Catcher in Moroccan mountains. (Source: Jacopo Prisco, CNN , “Desert ‘fog catchers’ make water out of thin air”)


Water dripping from the fog-catching mesh ((Source: Jacopo Prisco, CNN , “Desert ‘fog catchers’ make water out of thin air”)

Most likely, both mentioned above examples will be unrealistic at your off-grid location. However, it is good that you know about such technically feasible projects. Finally, you never know…

6. Water Hauling

Water hauling cannot be considered as a long-term solution for off-grid households. It will certainly be expensive, but possibly also unreliable solution in locations with difficult access by trucks. However, water hauling should be not discarded. In difficult times, it may be a “life-saving” backup option when weather conditions (for example long drought), excessive seasonal or accidental contamination or natural disasters will leave your taps dry.

Fortunately, there are several government-certified companies ready to transport the drinking water from reliable sources (in this case from a tap in municipal grid). Well, it’s sort of “last resort” solution that you may sporadically use. The positive part of such a scenario is that almost all off-grid water systems should have big water tanks acting as buffers between water source and user. They are necessary to accommodate seasonal fluctuation of levels of water from natural sources (inflows) and guarantee the constant amount of water available for everyday use (outflows). So it all comes to how to fill them!

Wendy’s Water Truck LLC (Pearblossom, CA, United States)

7. Diversification of water sources

Although these days we became so energy-dependent that for most of us it is difficult to think about life without electricity, we can still turn to “survival” mode (batteries, diesel generator, candles etc) when no other choice. However, the truth is that after a day without water we may not be able to think at all.

The right answer to water is diversification of its sources! Note, that rainwater really comes (falls) for free and can be easily harvested from the roof (also for free). There is nothing wrong to collect and use rainwater in a system parallel to well, spring or lake water source, especially for no-drinking applications. Do not give up easily on having “legendary” English Lawn around your off-grid house. It’s true, that you may have to trim it and water every second day for the last 100 years 😊. It’s also true that in England, water falls from the sky at almost any time. Probably Mother Nature will not offer you such luxury, but at least do not lose the opportunity when it comes (falls).

OK, more seriously – in off-grid environment (in this context often away from a grocery shop and green markets) growing your own basic veggies may be a tempting effort (an extra bonus will be their organic nature).

Even in an off-grid location, feeling the touch of Mother Nature, your own “arranged” nature is also “touching” …. 😊

The bottom line – whatever will be the source of your drinking water, do not forget that water is a “giver of life” so except for flooding, there is never too much water around. Gather as much as you can and use it wisely!

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