final assignment tots

8/2/2019 Final Assignment ToTS

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Tools of the Trade: Sustainability

Final AssignmentAn investigation into the differences in water consumption between

earthships and conventional suburban households

by Markolf von Ketelhodt

Image 1: Source : Epa : united states environmental agency


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Table of Contents

Final Assignment........................................................................................................................................1

An investigation into the differences in water consumption between earthships and conventional

suburban households.........................................................................................................................1

Image 1: Source : Epa : united states environmental agency...........................................................1

Foreword....................................................................................................................................................3

Introduction................................................................................................................................................4

Earthships...................................................................................................................................................5

Water Consumption....................................................................................................................................6

Table 1: Mexico Water Withdrawal & Precipitation Statistics.........................................................6

Graph 1: Water Withdrawal by Sector..............................................................................................7

Comparison between the water consumption of Conventional Houses and that of Earthships.................8

Table 2: Water Used per Activity for different methods..................................................................9

Graph 2: Bar Chart Comparison between Conventional and Water Saving Methods....................10

Illustration 1: Cross section of Earthship........................................................................................13

Table 3: Water Usage per activity of Conventional Households and Earthships...........................15

Graph 3: Earthship vs Conventional Households water consumption per activity........................15

Conclusion and Evaluation......................................................................................................................16

References:...............................................................................................................................................18

Appendix..................................................................................................................................................18


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Foreword

Throughout human history, never has there been a time where many of us live a life of plenty.

Through the rapid evolution of technological innovation the standard of living has increased

tremendously in almost all countries, arguably at different degrees. However, all this progress came

with a darker side that seems to increase at parallel with industrialisation, namely pollution and waste.Natural systems do not produce waste the same way we humans do. The waste of a tree, becomes the

food for countless organisms and eventually decomposes into nutrients and fertilizers for new plants.

Only recently have humans in the industrial age begin to realize that continued linear production of

products and consequential dumping of waste poses fundamental problems. These problems not only

negatively impact the environmental systems, but the very foundation that our civilization is built upon.

There is only a limited amount of time where one is able to recklessly cut down the rainforests, exploit

natural ecosystems and burn non-renewable fossil fuels. The reason for this are now becoming

increasingly intuitive for individuals to understand. Because of globalization and expansion of industry,

we have reached a point of realization that we live on a finite planet with finite resources. The

traditional way of recklessly exploiting natural resources has to come to an end, not only for the sake of

the environment, but for the sake of humanities well-being altogether. What then, are available

alternatives that we can adopt to function under more sustainable circumstances? The obvious point of

reference are the very systems we are currently destroying; the systems that function naturally.

Initiatives to implement such holistic modes of production have been developed and implemented to

some degree in the modern industrial civilization, with terms and practices such as 'recycling' and

'cradle-to-cradle' becoming ever more popular. However, many aspects of our modern life continue to

be inherently unsustainable. Even the 'patch-work' solutions to these problems, such as 'recycling' can

often be more wasteful in terms of energy use, than simply disposing the waste in conventional ways. If

the very nature of the socio-economic system that we have created is inherently unsustainable, then

even many of the tools we are attempting implement are simply not enough to right the many wrongs

of our system. Infinite economic growth, for all countries, can simply not occur on a planet with finite

resources. And this is especially true when a large portion of economic growth is fuelled by a rapidlydepleting non-renewable resource called oil.

It is clear that a fundamental paradigm shift is required to rethink the way we live our lives and

run our economies, which is perhaps a task to big for any government, organization or collective

governing body to undertake. What then can be done? The problem of course is that modern society

functions within a complicated web of a costly, inefficient and resource hungry infrastructure. The


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water that we drink, is often bottled in a different country than the one we call our home. The electricity

we - often wastefully - use is obtained through burning non-renewable fossil fuels, hydro-power which

requires a construction of a dam and flooding of a valley, nuclear power and other forms of electricity

generation which causes numerous environmental problems, economic challenges and has even results

in wars between nations. The majority of the food we eat is farmed in industrial-style mono-crop farmsand often requires hectares of land, the majority of our freshwater, and is sprayed with pesticides and

genetically modified, then 'fed' with artificial oil-based fertilizers. Then once its harvested, it must be

shipped and trucked over large distances until it reaches our plates. The hidden costs of our food is

almost incalculable, especially if you include the environmental impact of soil depletion, increase of

water toxicity due to the pesticides and fertilizers as well as the health costs involved with fighting

multiple-resistant bacteria that become immune to the antibiotics we use in livestock farming. These

hidden financial and environmental costs do not only apply to the realms of food production, but are

scattered throughout the industrial 'eco-system' (economic system) that we rely on.

Introduction

The aim of this paper is to introduce the reader to a means of living that can co-exist with the

current socio-economic structures in place today, but that is able to circumvent many of the

degenerative outcomes that result from the current system. The concept of an Earthship is at the heart

of one of the most sustainable initiatives and solution to the complex problems of the modern era. It

solves the problems associated to water scarcity, electricity production and use, food production andwaste disposal and recycling, all of which are encapsulated in the design and construction of a single

building called the Earthship. This paper will elaborate on the workings of such a building and how it

reduces its ecological footprint on a number of levels. To fully grasp the scope of the earthships

potential, it will be compared with conventional suburban households in regards to the many 'hidden'

costs of maintaining - and living in such buildings. At the end of this paper the reader will not only

have a clearer understanding of the problems associated with conventional housing and living practices,

but will develop an understanding and appreciation of alternative possibilities concerning sustainable

housing which not only shelters its inhabitants but is able to provide small-scales of food production,

waste management and other features that regular houses do not provide they rely on external

facilities to provide these services. Furthermore, this paper aims to show that if the concept of

earthships becomes fully utilized and replaces conventional suburban housing, that the stress on

modern infrastructure will be vastly reduced. Due to the limited scope of this investigation only water,

one aspect of housing is studied and compared in more detail. Quantitative arguments, in regards to


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water consumption will be used to strengthen the case and highlight the differences between

conventional housing and earthships. The two countries that are studied in this investigation concerning

water usage are the United States and Mexico.

Earthships

The concept of earthships has been developed over the past three decades by architect Michael

Reynolds. Earthships are passive-solar autonomous houses that are primarily build using natural or

recycled materials. Each building is designed to capture rainwater from its roof, produce its own

electricity using solar panels, processes its own waste through 'biocells' and produces a large amount of

food products for its inhabitants. The main building blocks of an earthships are discarded tires that are

pounded by hand and sledge hammer with earth to create a almost 200kg brick. These are not only

solid structures to build walls with, but they function as thermal mass, capable of storing and releasing

heat, through which they are capable of naturally regulating the indoor temperature. These principles

function much like a caves, that never get hotter, or colder than the outside environment. The thinner

walls of the interior are build using old soft-drink cans or plastic bottles plastered together to form a

light weight strong and durable wall. Using tires, plastic bottles, and tin cans as building materials

represents one the most effective form of recycling.

These buildings are all designed with sustainability in mind. Compared to conventional houses,

they do not rely on, or burden the national electricity grid, water services, waste disposal services and

to some extent the production and transportation of food. Furthermore, the earthships usage ofelectricity and water are designed in such a way to minimize and save every available kilojoule or drop

of water. For instance, where conventional houses require vast amounts of electricity to heat water and

their living rooms, earthships are designed to trap the natural heat of the sun, as well as using it to heat

water. Water is also used very differently than in conventional housing and these differences will be

discussed more in detail in the following chapters. Another key feature of the earthships is that they can

be designed and customized so that they can function in any climate. The birth of the first earthships

was in the desert of New Mexico, in close proximity to a small town called Taos. Here the summers can

get extremely hot, and the winters extremely cold, yet the inhabitants of earthships require no heating

or cooling systems, because the buildings are designed to allow maximum penetration of the sun into

the buildings during the winter months, and limits the amount of sun light warming the building during

the summer months. Furthermore, passive ventilation is also built into the structures to help regulate

temperatures. The key aspects and sustainable features are not completely unique to earthships. Solar

panels are generating power on conventional homes as well. However, earthships are one of the very


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few buildings that aim to be completely self-sustaining and as energy efficient as possible. One of the

most interesting distinctions between earthships and conventional houses can be made by investigating

the water usage of the two buildings. Investigating the differences between conventional houses water

consumption and that of an earthship will provide the best indications of how much more sustainable

and efficient these earthships are. This investigation will also postulate what it would mean in terms ofwater consumption, if every average household in the United States was replaced by an earthship.

Water Consumption

Fresh water is one of the most crucial natural resources life requires to exist on this planet. In

our industrial age this resource is being aggressively exploited at a much faster rate than it is being

replenished. This has tremendous implications on a number of different aspects of industry, domestic

and international prices of fresh water, structural implications of groundwater harvesting and even

affects international relations. A shocking case study that emphasizes one of the many implications of

uncontrolled fresh water harvesting is the situation of Mexico city. The mega metropolis of Mexico

City has been sinking into the ground due to the excessive depletion of the aquifer that lies beneath the

city. The sinking of the city does not occur evenly and results in many buildings collapsing (800 to

date) or tilting dangerously from their vertical axis. The city has condemned over 50 new structures

since 2006 because they are unsafe to live in. The cities main cathedral and the Sagrario Church

required 6 years and $33 million dollars to restore and preventing collapse. More than 380 fissures

have opened up and cracks appear on the surface, one of which a foot deep and longer than a mile inlength.1These and many other problems associated with the depletion of the water resources, coupled

with the constant threat of earthquakes makes Mexico City a costly project of restoration and

maintenance. These are all hidden costs of unregulated and excessive aquifer depletion. Most of these

problems could have been avoided if the depletion of the aquifers was more strictly monitored and

other methods of water harvesting, such as rain water harvesting would have been utilized.

To further investigate the problems associated with the depletion of aquifers and what potential

rainwater harvesting offers, the following data will be used:

1 http://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.html

Table 1: Mexico Water Withdrawal & Precipitation Statistics

Mexico Unit 1988-1992 1993-1997 1998-2002 2003-2007 2008-2012

Average precipitation in volume (10^9 m3/yr) 1477 1477 1477 1477 1477

Agricultural water withdrawal (10^9 m3/yr) 62.5 56.1 60.57 61.2

Industrial water withdrawal (10^9 m3/yr) 6.9 7.22 7.4

Municipal water withdrawal (10^9 m3/yr) 9.6 11.16 11.2

Total water withdrawal (10^9 m3/yr) 72.6 78.95 79.8
http://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.htmlhttp://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.html


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The table presents the data concerning water withdrawal for different sectors, as well as

precipitation for Mexico. It was obtained from the Aquastat database and the complete dataset can be

found in the appendix. The raw data as found on the Aquastat database poses a slight problem

concerning the validity of the data. For instance if we look at the 'average precipitation in volume'

variable, we find that the value of 1477 (10^9 m3/yr) is constant for the past 20 years. This of coursereflects a estimate of how much precipitation occurs, but does not reflect the reality. But for the sake of

this research assignment this data will be used, with the acknowledgement of certain inconsistencies

that can be found in any data set one comes across. The main point of this acknowledgement is that any

conclusions drawn in this assignment are only partially validated due to the uncertainty of the data.

Nonetheless, we can clearly see that total water withdrawal of all sectors in Mexico is about 5%

(79.8/1477) of the average annual precipitation. This shows that there is no lack of renewable water

falling from the sky each year. Essentially all of Mexicos water needs could theoretically be satisfied

using water from precipitation instead of natural aquifers. A problem concerning collection and

entrapment of precipitation as well as the distribution of it is rather obvious, which makes a complete

replacement of freshwater through precipitation very difficult to almost impossible. This becomes

increasingly relevant once you consider the information that the following pie diagram presents:

With 77% of all water withdrawal being attributed to the agriculture it becomes obvious that the

thirst of the farming sectors can not be quenched with rainwater harvesting techniques alone. However,

Graph 1: Water Withdrawal by Sector

77%

9%

14%

Water Withdrawal by Sector

Mexico

Agricultural water withdrawal

Industrial water withdrawal

Municipal water withdrawal


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the other thing the jumps out is that municipal water withdrawal is the second largest recipient of fresh

water. The FAOSTAT database definition of the Municipal water withdrawal is the annual quantity of

water withdrawn primarily for the direct use by the population, which includes renewable freshwater

resources as well as potential over-abstraction of renewable groundwater or withdrawal of fossil

groundwater and the potential use of desalinated water or treated waste water

2

. In the case of MexicoCity we can clearly identify that their primary source of freshwater is the fossil groundwater that has

been extract faster than it is replenished causing numerous problems. Although the municipal category

encompasses numerous buildings and facilities of the civilian population, a large amount of the water

consumed can be attributed to family households. Focusing on individual houses is important in the

context of this investigation, because its at individual households where rainwater harvesting can be

most effective specifically in the design of earthships.

The following part of this paper focuses on the differences between the water consumption of

conventional suburban households and that of earthships. The reason why earthships are being

compared to suburban conventional households is that they are more easily comparable than comparing

an earthship with say an apartment building in a city. Earthships are alone standing, solitary buildings

and are best compared to their equivalent counterpart of conventional communities.

Comparison between the water consumption of ConventionalHouses and that of Earthships

In order to compare the water consumption of both models, it is vital to form a coherent

appreciation of how much water the average household requires in conventional buildings. It is

impossible to get data for the exact amount of water each household uses, in each state or country.

Therefore this paper focuses on the average water consumption of a household in just one of the states

of the US. The state in question is Washington and the data was obtained from the Washington

Suburban Sanitary Commission and indicates how much water is used for a specific household activity.

No further information is given concerning how many people live in an average household nor was it

possible to find any additional meta-data on the website.3

The table on the following page is complied using information given by the WSSC, and is

manipulated into SI form in order better aid in this investigation.

2 FAOSTAT, Aquastat, Resources, Water:http://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251 ,28.03.2012

3 Washington Suburban Sanitary Commission: http://www.wsscwater.com/home/jsp/content/water-usagechart.faces
http://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251http://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251http://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251


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[Original values were converted manually from gallons into litres,

and are averages where necessary, see original table in the Appendix]

These figures will be used to get the general appreciation of how much water the average

household uses in the United States. Although this may differ from state to state, this paper assumes

that suburban houses in other states and countries use on average the same amounts of water than those

in Washington. The table shows two categories of how water is used in Washington; there is the

'Conventional' method, and the 'Water Saving*' method. The third 'grey' column represents the

calculated average between the 'conventional' and the 'water-saving' methods water consumption. The

estimates in the (AVERAGE) column will be used at a later stage to compare water usage betweenconventional houses and earthships. But before this can commence, it is important to describe in detail

the data manipulation that was undertaken in order to get these estimates, as well as do some

rudimentary data interpretation. This will help justify the data manipulation that took place.

For now, we shall concentrate on the two 'original' categories of the table, namely the

'conventional' and the 'water-saving' methods. The original estimates were not only converted from

gallons into litres, but in some cases, an average was taken between two estimates, in order to acquire

one value that is easier to work with. For instance, for the activity of 'Toilet (per flush)' the original

table provided the estimated amount of water being used for the 'conventional' method to be between 5

and 7 gallons. In order to convert these into workable SI values, I first converted each estimate

separately and then calculated the mean between the two values, which for the case of flushing toilets

the 'conventional' way is 45.43 litres per flush. This was done for all estimates that provided a range

rather than a concise value. Further more, concerning the estimates of water used for showering, the

meta-data on the website does not provide any explanation if these estimates are per person or per

Table 2: Water Used per Activity for different methods

ActivityLiters Used Liters Used Liters Used

(Conventional) (Water Saving*) (AVERAGE*)

Toilet (per flush) 22.72 9.47 16.095

Shower (per day) 386.1 136.32 261.21

Bath (full tub) 162.77 132.49 147.63

Laundry Machine (full load) 227.12 158.99 193.055

Dishwasher 56.78 33.12 44.95

Dish Washing by hand 113.56 56.78 85.17

Shaving 75.71 13.25 44.48

Brushing Teeth 37.85 9.47 23.66

Washing Hands 7.57 5.68 6.625

TOTAL 1090.18 555.57 822.875


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household. In fact, the original table indicates how much water is used 'per minute' in a shower, as

opposed to 'per day'. These estimates differ from the conventional shower to the water saving shower

(conventional shower = 32.18L/min and water-saving shower = 11.36l/min). Also, the meta-data

provided describes that a conventional shower takes between 7-10 minutes, where as a water-saving

shower takes between 12-15 minutes, which is a rather odd phenomena. Regardless of this, for thepurpose of this investigation I shall assume that the average household requires 12 minutes to shower,

which is about 3 minutes per person for a four people home. Because the other estimated amounts of

water used for the other activities presented in the table are 'per day' estimates, it was important to

convert the 'per minute' shower estimates into 'per day' estimates as well. The following bar chart

indicates how much water each household activity requires, on average each day, for both the

conventional and water-saving methods:

The bar chart on the previous page clearly indicates the differences in the amounts of water

being used between the two methods and also highlights which activities require the most amounts of

water. Clearly, showering in the conventional way requires the most amount of water compared to any

other activity and method . However, we also find that in the water-saving method, showering requires

less water than the laundry machine, which is not the case for the conventional method. These

differences are important to identify, specifically if we want to compare the water consumption of

conventional households (both 'water-saving' and 'conventional') with that of earthships.

Furthermore, Table 2 indicates the total amount of water being used for both types of water

Graph 2: Bar Chart Comparison between Conventional and Water Saving Methods

Toilet (per flush)

Shower (per day)

Bath (full tub)

Laundry Machine (full load)

Dishwasher

Dish Washing by hand

Shaving

Brushing Teeth

Washing Hands

0 50 100 150 200 250 300 350 400 450

23

386

163

227

57

114

76

38

8

9

136

132

159

33

57

13

9

6

Comparison between Conventional and Water Saving Methods(each activities water use (litres) for the average household)

Liters Used (Conventional)

Liters Used (Water Saving*)

Water Used (Litres)

Ac

tiv

ity


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using scenarios. The 'conventional' water usage requires approximately 1090.18 litres of water a day,

compared to the 'water-saving' houses that require about half (555.57 litres) of the water the former

uses. Because there are two different types of water usage evident in conventional housing and the

quantity used differs quite substantially, it remains a difficult process in comparing these estimates with

earthships, that have a completely different methodology of managing the water usage. One possibilityto circumvent this problem is to calculate the average water usage between the 'conventional' and the

'water-saving' methods in order to have one estimate viable for the comparison between earthships and

conventional suburban households as opposed to having two. This is why the third grey column

(AVERAGE) was added into Table 2. In the 'average' column we find that the total amount of water

being used is approximately 822.88 litres a day.

From this point on, the investigation will focus on the 'AVERAGE' litres of water used in

conventional housing. A more extensive and longer report would avoid such simplification of the data.

Nonetheless, the average total of 822.88 litres of water used in a household is a rather conservative

estimation, considering that this does not even include the out door water use for gardening, washing

cars, swimming pools etcetera.

Now that the technicalities regarding the data manipulation have been addressed, and the

interpretation of the data has taken place, it is time to compare the water consumption of conventional

households with that of earthships. In conventional housing each activity uses new/additional fresh

water from the pipes. What sets the earthship apart in this aspect is that it relies solely on rain or snow

water harvesting to meet the water requirements of the household. The roofs of earthships are designed

to channel every drop of rainwater and even dew through a silt catching filter into large underground

cisterns which store up to 4000 litres of water each. Many earthships have multiple cisterns in order to

trap as much water as possible during wet periods, so that they have enough water during drier periods.

The cisterns are designed to gravity feed a WOM (water organization module) which filters out bacteria

and contaminants, and makes it suitable for drinking. The WOM consists of a number of filters and a

DC pump which is powered by the solar panels on the roof. The pump is used to push the water

through the filters and into a conventional pressure tank to create normal household water pressure.

Conventional houses on the other hand, rely on water utilities to provide them with fresh water,

and different utility companies rely on different methods to providing fresh water to a thirsty

population. This paper has earlier demonstrated the problems associated with the conventional

management and supply of fresh water. The problems describe with Mexico City is one extreme

example which discussed most of the hidden costs associated with conventional methods of obtaining

and distributing fresh water. The earthships method of trapping rain water is a far more


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environmentally friendly and sustainable approach of acquiring fresh water. It needs to be stressed that

rainwater harvesting is not unique to earthships, nonetheless it remains an important difference between

earthships and conventional houses. Furthermore, the plumbing of earthships is designed to reuse a lot

of the waste water from different activities. Waste water can be distinguished between two categories;

grey water and black water. Grey water is the waste water generated from domestic activities, such aswashing dishes, washing hands, dishwashers, the waste water from showers etcetera, which can be

recycled on site. It differs from black water or toilet water that requires special sewage treatment. The

earthships plumbing is design in such a way that all of the grey water is recycled in a number of

different ways. Before the grey water can be reused, the earthships plumbing is designed to channel it

through a grease and particle filter and then into a rubber lined botanical cell. The botanical cell is

essentially a flowerbed inside (and/or outside) the living room of an earthship, which is comprised of

multiple layers. The bottom of such a cell is comprised of large rough gravel and rocks, which allows

water to pass through. On top of this layer, there is a layer of smaller gravel and sand, which divides the

larger rocks with the soil on top of it, which encourages plants (even edible plants) to grow. Throughout

the botanical cell oxygenation, filtration, transpiration and bacteria encounter all take place and help to

cleanse the water(Reynolds, 2000) through natural mechanism. The filtration of the grey water is

primarily achieved by passing the water through a mixture of gravel and plant roots. The plant roots

add oxygen to the water, remove nitrogen and absorb some of the water, which transpires through their

leaves. Natural bacteria will grow helping the plants fixate nitrogen and nitrates and further help

cleanse the water. The botanical cells floor is slightly sloped in order to gravity-pull the grey water

from one side to the other. Once it reaches the end of the cell it is directed through a peat moss filter

and then collects in a small reservoir or well. This semi-filtered grey water, although unfit for primary

reuse such as drinking or showering, can/and is used to flush conventional toilets or to water the

gardens. The main precautions that are necessary for the 'healthy' functioning of such a natural filtration

systems, is of course not to pollute them with toxins. In a conventional home, there are no immediate

consequences to the home owner when pouring dangerous chemicals down the drain. In an earthship,

this is discouraged, because if you pour something like paint thinner down your grey water drain, it will

not be healthy for the plants in the botanical cell. There are however, a number of biologically

degradable soaps, shampoos and cleaning agents that can be used in these systems. This, however

requires the conscious use of chemicals by the home owners of an earthship. This may seem limiting to

conventional home owners, but in terms of sustainability and environmental consequences, this

limitation may be viewed as negligible. Furthermore, earthships often have botanical cells placed both

indoors and outdoors. For the process of the grey water coming from sinks and showers an indoor


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botanical cell is used, and the outdoor botanical cells are used to process the grey water from washing

and dish washing machines as well as the over flow of the processed black water. Depending on the

size of the earthship, as well as the number of toilets it has, the grey water of washing machines and/or

dishwashers can also be processed indoors. To prevent flooding the indoor botanical cells, calculations

need to be made before hand to determine how many people will live in the earthship and use the toiletwhich will flush out the excess grey water.

The black water or toilet water, is non-reusable waste water and is sent to a outdoor solar-

enhanced septic tank which stores the sun's heat in its concrete mass to help anaerobic processes to

break down the solids. The excess semi-filtered black water over flows and is channelled into an

outdoor landscaping plant bed that is similar to the indoor botanical cells. This is also where the grey

water from washing and dishwashers end up in, if the indoor botanical cell is too small to process these

amounts of grey water. The following schematic illustrates the use of water in an earthship as well as

many of its other unique features that make it one of the most sustainable houses ever designed:

An earthship provides a small scale sewage treatment facility that is modelled after natural

decomposition and recycling processes. Furthermore, the flexibility of the earthships design allows it to

be connected to traditional utilities for water and waste management. However, this is often only done

in areas where there is either too little natural rainfall to satisfy the water needs (which rarely is the

Illustration 1: Cross section of Earthship


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case) or in areas of extreme climate, where outdoor temperatures are too cold to process the black water

waste. However, because of the ongoing innovation in the design of earthships, even these difficulties

are now overcome. In extremely cold climates such as Norway, earthships are designed with a double-

greenhouse, in which the outer green houses encapsulates the black water treatment botanical cells, and

the inner green house functions as the conventional grey water treatment botanical cells that allow foredible plants to be grown. These greenhouses also function as an crucial aspect of the interrior climate

control system, regulating temperature and humidity. Waste in an earthship is no longer seen as waste,

but as nutrients for other purposes. All this is not to say that an earthship does not produce any

chemical waste at all. Batteries need to be exchanged and disposed of every few years, so do light

bulbs, but the extent to which the waste is managed and disposed of is extremely reduced compared to

conventional houses.

The task of quantifying all of the sustainable features of earthships and comparing them with

conventional housing will prove to be a too large scope for this investigation. Solely concentrating on

the usage of water simplifies this task to a great degree. To compare the water usage of earthships with

conventional households a number of assumptions need to be made. Because earthships, much like

conventional houses differ in size and scope, I will assume that they require the same amount of water

for each activity as the 'average' conventional household does. This information is encapsulated in the

'grey' column of Table 2. The major difference of course lies in the fact that earthships require no

additional new water for flushing the toilets, but instead use grey water for this task. Furthermore,

earthships require no additional water for watering out door plants during dry periods, because their

waste water full fills this task. According to the WSSC the average household in requires between 630-

1860 gallons (2000-7000 litres) of water an hour for out door activities (see Appendix for table).

The other main difference between earthships and conventional houses, is that only a few

conventional houses actually make use of water saving devices, while a majority of them use the

conventional way. The exact ratio between how many houses use 'conventional' and 'water-saving'

methods is unknown, but the term 'conventional' indicates an implicit normality to the term, hence it is

rather likely that the majority of conventional households use the 'conventional' method of using water.

This further emphasizes the conservativeness of the estimated 'average' household usage. Nonetheless,

the water use in earthships is radically reduced because all earthships are designed to use low flow

show heads, low water use washing machines and other water saving devices. Therefore it can be

assumed that the water usage of the average earthship is similar to the 'water-saving' methods that some

conventional households have. In order to compare earthships with conventional houses, the estimates

of strictly 'water-saving' methods are attributed to the earthships and the calculated 'average' water


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usage, will be attributed to conventional households. These presumptions should be justified

considering the extensive descriptions and analysis offered on the previous pages.

The following table presents the assumed water consumption of earthships and the calculated

average water consumption of conventional households:

The following bar chart visualizes the information from the table and helps with comparing the

amounts of water being used per activity between earthships and conventional households:

Graph 3: Earthship vs Conventional Households water consumption per activity

Toilet (per flush)

Shower (per day)

Bath (full tub)

Laundry Machine (full load)

Dishwasher

Dish Washing by hand

Shaving

Brushing Teeth

Washing Hands

0 50 100 150 200 250 300

16

261

148

193

45

85

44

24

7

0136

132

159

33

57

13

9

6

Earthship vs Conventional Household

(comparrison of water consumption per activity)

Conventional Household

Earthship

Litres of Water

Ac

tiv

ity

Table 3: Water Usage per activity of Conventional Households and Earthships

ActivityLiters Used Liters Used

(Conventional Household) (Earthship)

Toilet (per flush) 16.10 0

Shower (per day) 261.21 136.32

Bath (full tub) 147.63 132.49

Laundry Machine (full load) 193.06 158.99

Dishwasher 44.95 33.12

Dish Washing by hand 85.17 56.78

Shaving 44.48 13.25

Brushing Teeth 23.66 9.47

Washing Hands 6.63 5.68TOTAL 822.89 546.1


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The one difference between the earthships water consumption and the 'water-saving' estimates

of conventional households, is that the earthship requires no additional water to flush toilets, because it

uses filtered grey water. This lowers the earthship water consumption by approximately 9.5 litres a day,

compared to the 'water-saving' estimates of conventional households. This may not seem like much, but

9.5 litres a day equate to 3467.5 litres a year, which are solely used for flushing a toilet.The graph on the previous page illustrates that the majority of the water used in earthships is

attributed to laundry machines. Another interesting thing about these graphs and the data provided by

the WSSC is that they indicate differences in water consumption between shaving, brushing teeth and

washing dishes by hand for different methods of water consumption. It seems in an earthship you use

less than half the water for shaving, than what you would use in a conventional household. These

differences cannot solely be attributed to physical water-saving devices, but are probably determined

by the way individuals use the water themselves. After all, leaving the tap running while shaving and

brushing teeth requires a lot more water than if you only use the tap when washing off the shaving

cream or tooth paste once your done. These differences in behaviour undoubtedly have a significant

influence on the water consumption of a household and are rather difficult to capture in a statistical

value or estimate.

Conclusion and Evaluation

Regardless of the many implications surrounding the data, and the many assumptions that were

necessary to arrive at a conclusion, this investigation has been able to provide a framework in which toestimate the differences in water consumption between earthships and conventional households. A

conservative estimate of the amount of water being used in conventional households is around 823

litres a day, which equates to a little over 300,000 litres a year. In comparison, earthships only use an

estimated 546 litres a day, equating to a little under 200,000 litres a year. This is 1/3 reduction of water

consumption by a single household. Furthermore, if you take into account that these 200,000 litres used

by earthships do not come from underground fossil water aquifers, large dams, or other conventional

fresh water sources, but from harvesting water from rain and snow fall, it becomes clear how much less

pressure is put on the environment.

The United States of America has a little over 300 million inhabitants, who live in

approximately 125 million houses. Not all of these house are alone standing 'conventional' households,

but if only one fifth (25 million) of these houses were replaced by earthships, that all harvest their own

rain water and take care of their own sewage, the US would save approximately 2.5 trillion litres of

water a year. Many of the technologies concerning water-saving can be implemented into conventional


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households as well. However, what sets the earthship apart, is that its efficiency in water use, is not its

only characteristic. The efficiency of its water management and recycling processes is just a fraction of

what earthships are capable of in terms of sustainability. Their electricity use is just as impressive as its

efficiency in reducing the amount of water it requires. More all-encompassing research needs to be

undergone in order to fully appreciate the benefits of earthships in quantitative terms. Nonetheless, thisinvestigation aimed to demonstrate one aspect of the effectiveness of the intelligent design of

sustainable housing. Earthships are just one of the more effective and impressive alternative sustainable

housing solutions, the use waste as building materials, and natural processes for electricity production

and water management. One of the more pressing issues concerning earthships is that their design will

be hard to incorporate into existing cities and high rise buildings. But there would be no problem in

replacing every single suburban household with an earthship, or retrofitting existing houses with the

technological mechanisms that make the earthship so sustainable. The only thing hindering the

expansion such efforts is the lacking appreciation of societies need for a sustainable revolution.


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References:

1. Seattle Times, Mexico City copes with that sinking feelinghttp://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.html

2. FAOSTAT, Aquastat, Resources, Water:http://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251 , 28.03.2012

3. Washington Suburban Sanitary Commission:http://www.wsscwater.com/home/jsp/content/water-usagechart.faces

4. Earthship Information: http://www.appropedia.org/Earthship, 28.03.2012

Appendix1. FAOSTAT raw data:

Mexico Unit 1988-1992 1993-1997 1998-2002 2003-2007 2008-2012

Total population 87523 95441 102634 109221 112033

Rural population 24264 24874 25317 25200 25173

Urban population 63259 70567 77317 84021 86860


National Rainfall Index (NRI) (mm/yr) 1199 1171 1052


Industrial water withdrawal (10^9 m3/yr) 6.9 7.22 7.4

Municipal water withdrawal (10^9 m3/yr) 9.6 11.16 11.2

Total water withdrawal (10^9 m3/yr) 72.6 78.95 79.8Municipal water withdrawal as % of total withdrawal (%) 13.22 14.14 14.04

Total water withdrawal per capita 707.4 722.8 712.3

Municipal water withdrawal per capita (total population) 93.54 102.2 99.97

Produced wastewater (10^9 m3/yr) 9.4 13.34

Treated wastewater (10^9 m3/yr) 1.92 2.596 3.11

Direct use of treated wastewater (10^9 m3/yr) 0.28

United States of America Unit 1988-1992 1993-1997 1998-2002 2003-2007 2008-2012

Total population 258276 272643 288467 302285 307687

Rural population 62009 59932 58320 56230 55394

Urban population 196267 212711 230147 246055 252293


National Rainfall Index (NRI) (mm/yr) 1020 1005 938.7


Industrial water withdrawal (10^9 m3/yr) 207.1 210.1 213 220.6

Municipal water withdrawal (10^9 m3/yr) 60.67 62.31 63.95 65.44

Total water withdrawal (10^9 m3/yr) 462.5 468 473.4 478.4

Municipal water withdrawal as % of total withdrawal (%) 13.12 13.31 13.51 13.68

Total water withdrawal per capita 1791 1717 1641 1583

Municipal water withdrawal per capita (total population) 234.9 228.5 221.7 216.5

Produced wastewater (10^9 m3/yr) 76.75

Treated wastewater (10^9 m3/yr) 48.71

Direct use of treated wastewater (10 9 m3/yr) 1.284

(1000 inhab)

(1000 inhab)

(1000 inhab)

(m3/inhab/yr)

(m3/inhab/yr)

(1000 inhab)

(1000 inhab)

(1000 inhab)

(m3/inhab/yr)

(m3/inhab/yr)
http://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.htmlhttp://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251http://www.wsscwater.com/home/jsp/content/water-usagechart.faceshttp://www.appropedia.org/Earthshiphttp://www.fao.org/nr/water/aquastat/data/popups/itemDefn.html?id=4251http://www.appropedia.org/Earthshiphttp://www.wsscwater.com/home/jsp/content/water-usagechart.faceshttp://seattletimes.nwsource.com/html/nationworld/2016310507_mexicosinking25.html


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2. Washington Suburban Sanitary Commission Data Tables:

3.

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