Basic Water Requirements for Human Activities:Meeting Basic Needs

by Peter H. Gleick, M. IWRAPacific Institute for Studies in Development, Environment, and Security1204 Preservation Park WayOAKLAND CA 94612U.S.A.E-mail: pgleick@pipeline.com

INTRODUCTION

The last few years have seen a remarkable change inthe nature of the global discussion of issues ofenvironmentand development. In the work of the Brundtland Com-mission [I], the extensive lead-up to the 1992 EarthSummit in Brazil, and in subsequent discussions andwork, the intimate connections between environment anddevelopment have been accepted as a given. The questionsnow being discussed and researched are how to defineand achieve development in a “sustainable” way. This isa much needed and welcome change.

Unfortunately, considerable debate and confusion sur-round both the terms “sustainable” and “development”and only modest forward progress has been made. Thislack of progress is particularly disturbing in the area ofwater resources, which are vitally important for producingfood, maintaining aquatic ecosystems, and protectinghuman health.

Among the concepts raised nearly 20 years ago duringthe 1917 Mar de1 Plata conference - one of the earliestinternational efforts to address global water problems -was that of “basic needs” [2] :

alI peoples, whatever their stage of developmentand their social and economic conditions, have theright to have access to drinking water in quantities andof a quality equal to their basic needs.

This concept was strongly reaffirmed during the 1992Earth Summit in Rio de Janeiro and expanded to includeecological water needs [3]:

In developing and using water resources, priority hasto be given to the satisfaction of basic needs and thesafeguarding of ecosystems.Implicit in this phrase is the idea of minimum resource

requirements for certain human and ecological functions,and the allocation of sufficient resources to meet thoseneeds, This article defines and quantifies “basic waterrequirements” (BWRs) in terms of quantity and qualityfor four basic human needs: drinking water for survival,

water for human hygiene, water for sanitation services,and modest household needs for preparing food. Theconcept of identifying water needs for growing food andprotecting natural ecosystems is also briefly discussed.These minimal needs are also discussed in the context ofinternational water law and two regions with a long historyof water disputes: the Middle East and California. Finally,data are presented showing the current failure of manynations to provide even this basic level of clean water totheir citizens.

Based on the analysis here, I recommend that inter-national organizations, national and local governments,and water providers adopt a basic water requirementstandard for human needs of 50 liters per person per day(l/p/d) and guarantee access to it independently of anindividual’s economic, social, or political status. Unlessthis basic need is met, large-scale human misery andsuffering will continue and grow in the future, contributingto the risk of social and military conflict. Ultimately,decisions about defining and applying a basic water re-quirement will depend on political and institutional fac-tors, but the concept may prove useful in meeting basicwater needs for the next century.

DEFINING BASIC WATERREQUIREMENTS

Different sectors of society use water for different pur-poses: drinking, removing, or diluting wastes, producingmanufactured goods, growing food, producing and usingenergy, and so on. The water required for each of theseactivities varies with climatic conditions, lifestyle, culture,tradition, diet, technology, and wealth, as shown over 20years ago in the groundbreaking work of White, Bradley,and White [4]. The type of access to water alone is animportant determinant in total water use. Tables 1 and2 show that the level of domestic water use varies withdistance from the water source and with the climate.

The term “water use” encompasses many different ideas

0250-8060/96/$3.30 Water International, 21 (1996) 83-92 0 IWRA/Printed in the U.S.A.

Table 1. Domestic water use by distance to source

Source of water

Public Standpipe,farther than 1 kilometer

Public Standpipe,closer than 1 kilometer

House Connection,

less than 10

20

simple plumbing, pour, flush toiletHouse Connection,

60 to 100

urban, with gardens 150 to 400

and is often misleading and confusing. Among otherthings it has been used to mean the withdrawal (intake)of water, gross water use (intake plus recirculation plusreuse), and the consumptive use of water. In this article,I use the term “withdrawal” to refer to the act of takingwater from a source to convey it elsewhere for storage oruse. Not all water withdrawn is necessarily consumed,however. Indeed, for many processes, water is often with-drawn and then returned directly to the original sourceafter use, as in water used for cooling thermoelectricpower plants. Gross water use is distinguished from waterwithdrawal by the inclusion of recirculated water. Thusfor many industrial processes, far more water is requiredthan is actually withdrawn for use. Water “consumption”or “consumptive use” is taken here to mean the use ofwater in a manner that prevents its reuse, such as throughevaporation, plant transpiration, contamination, or in-corporation into a finished product. When the term water“use” is given, it refers to the amount of water requiredto meet a specific need or to accomplish a particular task.

Minimum Drinking Water Requirement

An absolute “minimum water requirement” for humans,independent of lifestyle and culture, can be defined onlyfor maintaining human survival. To maintain the waterbalance in a living human, the amount of water lostthrough normal activities must be regularly restored.While the amount of water required to maintain survivaldepends on surrounding environmental conditions andpersonal physiological characteristics, the overall vari-ability of needs is quite small. Routes for water lossinclude evaporation from the skin, excretion losses, andinsensible loss from the respiratory tract. Humans mayfeel thirst after a fluid loss of only 1 per cent of bodilyfluid and be in danger of death when fluid loss nears 10per cent [7 ] .

Prior physiological studies have generated “referencevalues” for a daily human water requirement. Table 3summarizes several estimates of total daily water require-ments for a “reference” human. Minimum water require-ments for fluid replacement have been estimated at aboutthree liters per day under average temperate climateconditions. When climate and levels of activity are changed,these daily minimum water requirements can increase.In a hot climate, a 70-kilogram human will sweat between

Table 2. Rural household water use by climate and source’

Public Stand- House Connec-Climatic Zone post tica?

liters/capita/day liters/capita/day

Humid IO too 20 20 to 40Average 20 to 30 40 to 60Dry 30 to 40 60 to 80

-Data from rural developing countriesb Without flush toilets OF gardens.Source: Reference 5.

four and six titers per day without a. comparable changein food intake or activity [7].

The National Research Council of the National Acad-emy of Sciences in the U.S.A. separately estimated min-imum human water requirements by correlating themwith energy intake in food. They recommend a minimumwater intake of between one and one-and-a-half millilitersof water per calorie of food (1 - 1.5 ml/kcal). Note thata food calorie is equivalent to a kcal of energy. In thisarticle, the energy content of food will be represented bykcals. This does not include the water required to growthe food consumed, which is discussed later. With rec-ommended daily diets ranging from 2,000 to 3,000 kcals,minimum water requirements are between 2,000 and4,500 milliliters, or 2 to 4.5 liters per day-comparablewith the data presented in Table 3 [ 14].

Using these data, a minimum water requirement forhuman survival under typical temperate climates withnormal activity can be set at three liters per day. Giventhat substantial populations live in tropical and subtrop-ical climates, it is necessary to increase this minimumslightly, to about five l/p/d, or just under two cubic metersper person per year. A further fundamental requirementnot usually noted in the physiological literature is thatthis water should be of sufficient quality to prevent water-related diseases.

Basic Requirements for Sanitation

A “minimum” must also be defined for providingsanitation services. There is a direct link between theprovision of clean water, adequate sanitation services, andimproved health. Extensive research has shown the clearhealth advantages of access to adequate sanitation facilities

Table 3. Average daily water requirements for survival’

Average daily waterintake in liters per

Source capita per day

Vinograd [8]; Roth [ 9 ] 2.5bWorld Health Organization [IO] 2.5White et al. [4] I.8 to 3.0U.S. Environmental Protection Agency [I 1] 2.0National Academy of Sciences [ 12] 2.0Saunders and Warford [ 13] 5

‘During normal activity and temperate climate.bThi~ value represents the actual fluid requirements measured forearly space flights. The recommended intake minimum for Apolloastronauts under routine conditions in the command module was 2.9liters per day.

84 Water International

and protecting drinking water from pathogenic bacteriaand viral and protozoa1 agents ofdisease. Effective disposalof human wastes controls the spread of infectious agentsand interrupts the transmission of water-related diseases.

Unfortunately, much of the world’s population, partic-ularly in developing countries, remains without access toclean drinking water or adequate methods to dispose ofhuman wastes. According to recent estimates, more than1.7 billion people lacked access to adequate sanitationservices in 1990, while over 1.2 billion people lackedadequate clean drinking water [15]. During the decadebetween 1990 and the year 2000, nearly 900 million morepeople will be born in these regions [16,17]. It has beenestimated that lack of clean drinking water and sanitationservices leads to many hundreds of millions of cases ofwater-related diseases and between five and ten milliondeaths annually, primarily of small children [ 18-21].

For the most part, the world health community knowshow to prevent these diseases, but lacks the financial andinstitutional capability needed to take definitive and ef-fective action. While media attention to these problemsincreases when particularly acute regional crises occur,such as the recent disastrous outbreak of cholera in LatinAmerica or among Rwandan refugees in Zaire, the morewidespread chronic problems still beg for attention fromthe world community.

In recent reviews of epidemiological studies related towater and sanitation, the provision of adequate sanitationservices was the most direct determinant of child healthafter also providing a minimum amount of water formetabolic activity and handwashing [ 19,20,22-24].

There are many technologies for improving access toadequate sanitation services, with widely varying waterrequirements. In regions where absolute water quantityis a major problem, alternatives that require no water areavailable. Table 4 lists those technologies that require nowater except for minimal washing. Where historical cir-cumstances led to the use of wasteful, high-volume flushtoilets, as much as 75 liters per capita per day, or more,have been used. Table 5 lists the wide range of sanitationtechnologies that require water. The choice of sanitationtechnology will ultimately depend on the developmentalgoals of a country or region, the water available, theeconomic choice of the alternatives, and powerful regu-latory, cultural, and social factors [4,25].

Given these variables, can a recommended basic waterrequirement for sanitation be identified? Because alter-natives are available that require no water, it is technicallyfeasible to set a minimum at zero. Two factors argueagainst doing this: additional health benefits are identifi-

Table 4. Sanitation technologies that require no water

Ventilated improved pits (VIP)Reed Odorless Earth Closets (ROEC)Ventilated Improved Double-Pit LatrinesDouble-Vault Comporting Toilets (DVC)Continuous Composting

Sources: References 25 and 26

Vol. 21, No. 2 (1996)

able when up to 20 liters per capita per day of cleanwater are provided [23]; and where economic factors arenot a constraint, cultural and social preferences stronglylean toward water-based systems. Access to some waterfor sanitation, together with concurrent education aboutwater use, decreases the incidence of diseases, increasesthe frequency of hygienic food preparation and washing,and reduces the consumption of contaminated food prod-ucts. Accordingly, while effective disposal of human wastescan be accomplished with little or no water when nec-essary, a minimum of 20 liters per person per day isrecommended here to account for the maximum benefitsof combining waste disposal and related hygiene, and topermit for cultural and societal preferences. This levelcan be met with a wide range of technological choices.

Basic Water Requirement for Bathing

On top of these direct sanitation requirements, addi-tional domestic water is used for showering or bathing.A review of a range of studies in North America andEurope (Table 6) suggests average (not minimum) wateruse in industrialized nations for bathing to be about 70liters per person per day, with a range from 45 to 100l/p/d. Data on water used for bathing in developingcountries or in regions with no piped water are not widelyavailable. Some studies suggest that minimum waterneeded for adequate bathing is on the order of 5 to 15 1/p/d and that required for showering is 15 to 25 l/p/day[25]. A basic level of service of 15 l/p/d for bathing isrecommended here.

Basic Requirement for Food Preparation

The final component of a domestic basic water require-ment is the water required for the preparation of food.While most detailed surveys of residential water use inindustrialized countries do not provide separate estimatesof water used for cooking, Brooks and Peters [29] estimatethat water use for food preparation in wealthy regionsranges from 10 to 50 liters per person per day, with amean of 30 liters per person per day. In a study done ofthe water provided for 1.2 million people in northernCalifornia, an average of 11.5 liters per person per daywas used for cooking, with an additional 15 liters usedfor dishwashing [31]. Other studies in both developedand developing countries [4,14,32,33] suggest that anaverage of 10 to 20 liters per person per day appears tosatisfy most regional standards and that 10 l/p/d willmeet basic needs.

The Special Case of Food

The four domestic uses described above do not includewater required to grow the food necessary for humansurvival. Minimum caloric requirements, cultural pref-erences for different kinds of food, regional climaticconditions, irrigation and food processing technologies,

85

‘.

Table 5. Sanitation technologies that require water

Sanitation Technology

Pit latrinePour/Flush (PF) toiletsVault toilets and cartageSewered PF toilets/septic tanks li’ ’Small-b-are sewerage .iInefficient conventional sewerage

Water Requirement Minimum Water

Water near toilet 1 to 2 liters/flushWater near toilet 6 to 10 liters/person/dayWater near toilet 3 to 6 liters/person/dayWater piped to toilet 7.5 liters/person/dayWater piped to toilet >50 liters/person/dayWater piped to toilet >75 liters/person/day

Sources: References 25 and 26.

and a wide range of social factors all affect total waterrequirements for producing food. At present, no satisfac-tory analysis of these factors has been done. Roughcalculations, however, offer some insight into how variablethese factors can be.

Typical regional diets, compiled from the UN Foodand Agriculture Organization [34], are shown in Table 7.Using average evapotranspiration requirements on a re-gional basis, estimates of rainfed and irrigated acreage,and assumptions about the efficiency of irrigation cangive a first-order estimate of the water requirements toproduce these regional diets. In fact, however, calculatingactual water requirements to grow food is even morecomplicated. Among the other factors that must be con-sidered are specific regional crop yield information, soilconditions, more precise climatic variations and effects,food processing and waste factors, and so on.

No comprehensive estimates have yet been made, thoughthere have recently been efforts to make some regionalestimates. Table 8 shows the estimated water requirementsthat would be necessary to grow the food needed to meetdietary demands in three arid regions: California, Egypt,and Tunisia [35]. California is a region with heavy meatconsumption and heavy irrigation water needs. Tunisiaand Egypt have much lower meat consumption, andTunisia provides a comparatively lower fraction of agri-cultural water with irrigation. As this table shows, thewater required to grow food is far above - by as muchas two orders of magnitude-the basic water require-ments for domestic human needs. Far more work isrequired, however, to actually determine “minimum”agricultural water needs to meet specific diets, as opposedto the average values provided in Table 8.

The water required to grow food must be considered aspecial case for several other reasons. Unlike the BWRfor human survival and domestic use described in the

previous section, food can be produced in water-richregions and transported to water-poor regions. In fact,this occurs today on a vast scale and is only constrainedby internal political policies that push for domestic foodsecurity, by economic problems related to import/exporttrade balances, and by transportation difficulties. As aresult, providing a BWR for food production, howeverdefined and quantified, should be considered indepen-dently from the responsibility of governments for provid-ing the BWR for maintaining human survival and health.

Basic Water Requirements for Natural Ecosystems

No attempt is made in this paper to define and quantifyprecise BWRs to protect natural ecosystems, though theprinciple that some water be guaranteed to maintainecosystem health has also been put forward [3,36]. I ntraditional water planning and management, the waterneeds of the natural environment are rarely consideredor guaranteed. In the United States and Europe, someminimum flow requirements have been set for rivers andsome minimum quality or temperature standards havebeen promulgated to protect environmental assets. In theUnited States, legislation has protected stretches of certainpristine rivers from development, and some water hasbeen reallocated from major water projects and users tothe environment. In California, for example, a combi-nation of federal and state laws has set aside nearly 30,000million cubic meters (mcm) of annual runoff for envi-ronmental purposes, including the protection of wild andscenic rivers, the Sacramento-San Joaquin Delta, andinstream and wetlands flow protections for fish and wa-terfowl [30,36]. This represents nearly 28 per cent of totalannual average runoff from the state. Similar legal effortsare under way internationally. In 1994, for example, theInternational Law Commission (ILC) produced a set of

Table 6. Average residential end-use of water in developed countries (liters per person per day)

End UseToiletsBath/Shower

LaundryKitchenYard/Other

Total Use (l/p/d)

Unitedstates

[27]2:

454575

295

Unitedstates

[ 2 8 ]9575

501511

246

Sweden[27]4070

305025

215

severalThe North Avge. Northern

Nether- Amer. Massa- Cali- Cali-lands Cities chusetts fornia fornia1271 [ 2 9 ] [29] [30] [31]39 84 127 10927

:73 99 78

I7 33 29 7117 31 22 56 z;4 5 4 178 171

104 225 212 531 171

86 Water International

Table 7. Average Regional Diets, 1989 (Calories per person per day)

articles setting forth principles to guide the behavior ofstates. Article 20 explicitly requires “watercourse States”to “protect and preserve the ecosystems of internationalwatercourses” [48].

sociated with these other sectors reflect human “wants”and not “basic needs,” these demands should be providedonly after basic human needs are met.

Despite these efforts, aquatic ecosystems throughoutthe world are under severe stress and threat of destruction.Globally more than 700 species of fish alone are consid-ered threatened with extinction [37]. In the last coupleof years, several have been added to the list, includingmajor anadromous fish species. Basic water requirementsto protect these species and, more broadly, whole ecosys-tems, must be identified and provided.

MEETING BASIC NEEDS: ARECOMMENDATION FOR AGUARANTEED BASIC WATERREQUIREMENT

Ultimately, society will have to make decisions aboutwhich ecosystems should be maintained or restored andthe indicators by which to measure their health. Then,minimum allocations of environmental water will haveto be made on a flexible basis, accounting for climaticvariability, seasonal fluctuations, and other factors, Eco-system management will have to be flexible, with decisionsreviewed frequently based on the latest information. Ear-ticular care must be taken when human actions mightlead to irreversible effects.

Other Water Requirements

There are many other human uses of water, includingwater for industrial and commercial use, and for powerplant cooling and electrical generation. Water require-ments to meet these demands depend on what preciselyis being produced, on the technology used, and on a hostof other characteristics. Detailed analyses are needed toevaluate these demands, but a wide range of requirementsis described in Gleick [ 15]. Because water demands as-

Table 9 summarizes the water requirements for drinkingwater, hygiene, sanitation services, and food preparation.Recommended levels are based on fundamental healthconsiderations and on assumptions about technologicalchoices usually made at modest levels of economic de-velopment. Considering drinking water and sanitationneeds only suggests that the amount of clean waterrequired to maintain adequate human health is betweentwo and 80 liters per person per day, or up to about 30cubic meters per person per year. The low end of thisrange is an absolute minimum and reflects survival only.The upper end reflects a more complete satisfaction ofbasic needs using water piped directly to the house andtoilet. This article recommends that a BWR of 25 litersper person per day of clean water for drinking andsanitation be provided by water agencies or governments.

This amount is just above the lower end of the 20 to40 liters per person per day target set by the US. Agencyfor International Development, the World Bank, and theWorld Health Organization, each of which also excludewater for cooking and cleaning. It is also in line with therecommended standards of the United Nations Interna-tional Drinking Water Supply and Sanitation Decade andAgenda 21 of the Earth Summit.

Total daily water input (l/p/d)

Percentage of water needed toproduce meat in diet (%)

California Egypt Tunisia

5,908 3,242 2,96464.0 21.4 26.9

Percentage of total daily water inputmet by irrigation (%)

71.4 69.0 57.3

Adding water for bathing and cooking raises the totalrange to between 27 and 200 liters per capita per day,bracketing the level of 100 liters per capita per dayidentified by Falkenmark and others [38,39] as typicalhousehold demand in water-scarce regions. Falkenmarkconsiders 100 l/p/d to be necessary to provide for someminimum acceptable quality of life [Falkenmark, personalcommunication, 1996]. The upper end of the range isequal to an annual need of about 75 cubic meters perperson (m’/p/yr). During recent severe drought in Cali-fornia, domestic water use in some of the wealthiest (but

Vol. 21, No. 2 (1996) 87

Table 9. Recommended basic water requirements for human needs’

Purpose

RecommendedMinimum(liters perperson per

day)

Range(liters perperson per

day)Drinking WateP 5 2 too 5Sanitation Services’ 200 t o overr 75Bathing 5 to 7odCooking and Kitchen 10 t o sodTotal Recommended BasicWater Requirement 50*Excluding water required to grow food (see text).0 This is a true minimum to sustain life in moderate climatic conditionsand with average activity levels.c A n average (not minimum) of 40 l/p/d is considered adequate fordirect sanitation hookups in industrialized countries. The upper endof the range represents extremely inefficient toilets. In water-shortregions, sanitation systems that use no water are available, but rarelyembraced socially.d The upper valuer here represent societal preferences for moderatelyindustrialized countries. Use in some water-rich regions may exceedthese amounts. The lowest valuer reflect minimum uses in developingcountries.

water-short) regions was rationed to the equivalent ofabout 70 m’/p/yr. These levels were achieved without anysevere hardships, even in communities accustomed to farhigher levels of household water use [40].

Using minimum levels of 15 l/p/d for bathing and 10l/p/d for cooking, I recommend here that internationalorganizations and water providers adopt an overall basicwater requirement (BWR) of 50 liters per person per dayas a new standard for meeting these four domestic basicneeds, independent of climate, technology, and culture.While biiions of people lack this standard today, it is adesirable goal from both a health perspective and from abroader goal of meeting a minimum quality of life.

To what extent does a state have an obligation toprovide its citizens with a basic water requirement? Shouldthe international legal community consider the right to acertain level of fresh water to be a basic human right?McCaffrey [4 1] has extensively explored international legalframeworks and law and concludes that there are obstaclesto the establishment in international law of the humanright to water as a binding obligation on states. He goeson to say, however, “it is clear that, at least in some form,the right may be inferred under the basic instruments ofinternational human rights law? He further argues thatthe devastating consequences of being denied such watershould require that relevant provisions of existing humanrights instruments “ought to be interpreted broadly, so asto facilitate the implementation of the right to water asquickly and comprehensively as possible? The two in-ternational declarations quoted at the beginning of thisarticle also suggest that states have the obligation todevelop in such a way as to ensure that their use of freshwater is sustainable and adequate to meet the basic needsof its people. These declarations provide additional support for the conclusion that there is both a basic right towater.

I argue here that the right to water sufficient to meet

basic needs should be an obligation of governments, watermanagement institutions, or local communities. While insome regions, governmental intervention may be neces-sary to provide for basic water needs, many areas will beable to use traditional water providers, municipal systems,or private purveyors within the context of market ap-proaches. Unfortunately, there are many reasons whygovernments or water providers may be unable to providethis amount of water, including rapid population growthor migration, the economic cost of water-supply infras-tructure in regions where capital is scarce, inadequatehuman resources and training, and even simple politicalincompetence. Nevertheless, failure to provide this basicneed is a major human tragedy. Preventing that tragedyshould be a major priority for local, national, and inter-national groups,

How would a proposal for providing a BWR be im-plemented? Defining and applying this principle mightrequire that the BWR be made available to all inhabitantsof a hydrologic region (such as a watershed or the areaoverlying a groundwater aquifer) prior to resolution ofhow to distribute remaining water resources. In areasserved by municipal systems, subsistence water charges -lifeline rates - for basic levels would ensure provision ofa minimum level of service to all users. Such rates havebeen used for many years by energy utilities and are nowbeginning to appear in water utility rate design. In regionallong-term water planning, providing a BWR to all inhab-itants should be set as the highest priority-togetherwith identifying and providing a BWR for the naturalenvironment-before allocations are made for otheruses. In international river basins, such allocations willalmost certainly require joint basin committees empow-ered to make binding management decisions for the region[42].

PROGRESS TOWARD MEETING BASICHUMAN WATER NEEDS

Vast regions of the world and hundreds of millions ofpeople lack the water required to meet the basic humanneeds proposed above. While the traditional measure ofwater scarcity has been per-capita water availability [49],it is now possible to begin to use data on actual wateruse-a measure more representative of actual humanwell-being. Using the BWR as a benchmark, Table 10lists those countries whose reported domestic per-capitawater withdrawals fail to provide 50 liters per capita perday. According to these data, in 1990 fifty-five countrieswith a population of nearly a billion people fell belowthe level recommended in this article. There are actuallyeight countries whose total reported water use in a l lsectors falls below the recommended BWR for just basichuman needs.

In fact, there are strong reasons to believe that theactual number of people failing to receive the recom-mended BWR is far above the numbers reported here.

88

The data in Table 10 are country averages, and severallarge countries, such as India and China, report that theiraverage domestic water use slightly exceeds 50 liters perperson per day. We know, however, that average nationalwater-use data hide significant regional variations, withlarge segments of populations usually falling below theaverage, while wealthier portions of the population tend

Table 10. Countries with total domestic water use below 50 1/p/d

Country

GambiaMaleSomaliaMozambiqueUgandaCambodia

TotalDomestic

Total Use as a1990 Domestic

PopulationPercentage

Water use of the BWR(million in liters/ of 50 liters perpeople) person/day person per day

0.86_.__ 4.5 09.21 8.07.50 8.9

15.66 9.3

TanzaniaCentral Africa RepublicEthiopiaRwandaChadBhutanAlbaniaZaireNepalLesothoSierra LeoneBangladeshBurundiAngolaDjiboutiGhanaBeninSolomon IslandsMyanmarPapua New GuineaCape VerdeFijiBurkina FasoSenegalOmanSri LankaNigerNigeriaGuinea-BissauVietnamMalawiCongoJamaicaHaitiIndonesiaGuatemalaGuineaCote D’lvoireSwazilandMadagascarLiberiaAfghanistanUruguayCameroonTogoParaguayKenyaEl SalvadorZimbabwe

18.798.25

27.323.04

49.247.245.681.523.25

35.5719.14

1.774.15

115.595.47

10.020.41

15.034.630.32

41.683.870.370.769.007.331.50

17.227.73

108.540.96

66.698.752.272.466.51

184.289.205.76

12.000.79

l2.002.58

16.563.09

11.833.534.28

24.035.259.71

9.39.5

10.113.213.313.613.914.815.516.717.017.017.117.318.018.318.719.119.519.719.819.920.020.322.225.426.727.628.428.428.528.829.729.930. I30.234.234.335.235.636.437.237.339.339.642.643.545.646.046.248.2

1618191919

::

::2830

::3434

:::36373738

:;404040

:

::5557575758

z6060

2;707173747579

:;

;:

;:96

Data on domestic water use come from References 15, 43, and 44. Sources: Population data from Reference 55.

Vol. 21, No. 2 (1996)

to use far more per capita. In addition, the national wateruse data used in Table 10, while the best available, areknown to be inadequate. For example, there are severalcountries on this list that are relatively water-rich, sug-gesting the possibility that official data on water with-drawals may miss substantial domestic water use that isself-supplied. Improving the scope, quality, and extent ofwater use data is vitally important.

An additional problem is that there are few data toindicate the typical qualify of the water received. Poorquality of domestic water is a severe and widespread.problem, and it is likely that many people who mayreceive more than the recommended quantity are gettingcontaminated and unhealthy water. Furthermore, popu-lation growth is increasing in most of these regions fasterthan improvements to water availability,

In contrast to these figures, domestic water use in allindustrialized countries far exceeds the BWR, though thequality of this water varies widely. In the countries ofwestern Europe, the recommended BWR is typically lessthan 25 per cent of total domestic use. In the U.S. andCanada, a BWR of 50 l/p/d is less than 10 per cent oftotal current domestic use.

What might this BWR concept imply in regions wherepolitical conflicts over water resources are prevalent, suchas the Middle East? Table 11 shows United Nationsmedium population projections for the parties of theJordan Basin [45] and the water required to provide thispopulation with a BWR. Guaranteeing the 1990 popu-lation of Israel, Jordan, and the West Bank with just abasic annual water requirement of 50 liters per personper day would require about 180 million cubic meters(mcm) of water annually. By 2025, this amount wouldrise to over 400 mcm. These quantities also exclude anydemands from Syria and Lebanon, portions of whosepopulation rely on water from the Jordan River basin.Estimates of the total annual renewable freshwater avail-ability for all of Israel, Jordan, and the West Bank, areunder 3,400 mcm. In the Jordan River basin, a proposalto guarantee the population a basic water requirementcould mean allocating 50 l/p/d to all inhabitants of thebasin before negotiating shares of remaining water among

Table 11. Populations and basic water requirements in the JordanBasin

Population Total Water Needed Total Water Needed(1,000s) to Satisfy BWR to Satisfy BWR

of 50 I/p/d of 50 1/p/d1990 2025 (for 1990 in mcm/vr) (for 2025 in mcm/vr)

Jordan 4,2599 12,039 78Syria 12,348 33,505 225

Israel 4.660 7,808Lebanon 2,555 4,424 ::West Bank’ 975 2.500 18

‘The UN does not include separate estimates of West Bank populationand no recent census has been conducted. Future growth rates arehighly dependent on uncertain immigration rates. A population of 2.5million in the year 2025 was assumed here, but could be substantiallyhigher or lower.

89

the riparians (Syria, Lebonon, Jordan, Israel, and thePalestinians). In international basins, such a policy wouldrequire setting up institutional structures, such as a JointRiver Basin Commission, to monitor agreements andallocate water. The recent peace treaty between Israel andJordan provides the beginnings of such a basin commis-sion.

Shuval [46,47] and Gleick [42] each raised the conceptof applying a minimum water requirement in the contextof the water disputes in the Middle East. In both ap-proaches, their “minimum” levels included considerableamounts of water required for human uses in additionto the basic needs described above.

Shuval [46] set a minimum at 125 cubic meters perperson per year in order to satisfy domestic needs as wellas modest industrial and gardening needs. Gleick [42]proposes a lower minimum - 75 cubic meters per personper year - also including some industrial and commercialactivities. Using the higher levels proposed by Shuvalwould increase the total minimum demand in the regionto 1,200 mcm/yr in 1990 and about 2,800 mcm/yr by2025. This latter amount approaches the total for thereliable supply in the entire Jordan Basin. Satisfying tbislarger “minimum” would require taking almost all thewater now used to grow food and applying it to meetdomestic and industrial needs. This implies major restruc-turing for the region’s agricultural water policy-a re-structuring that has already begun.

In California, like the Middle East, growing populationsare coming up against natural water constraints. WhileCalifornia water planners and policymakers have managedto stave off these constraints in the past through massiveinfrastructure development, the era of building new largedams, reservoirs, and aqueducts is drawing to a close.The current dilemma facing California water managersis how to meet new demands using new approaches.Under traditional water projections, Californians face ashortfall of more than two billion cubic meters per yearby 2020, more than one billion cubic meters ofpermanentgroundwater overdraft, declining ecosystem health, andcontinued inefficient water use in almost all sectors [30].This kind of traditional forecast, while highlighting thenature of current problems, no longer offers any guidanceon how to develop sustainable water policies.

A new approach presents a sustainable vision for Cal-ifornia’s water resources in the year 2020 [36]. In thisanalysis, seven criteria for sustainable water use are pre-sented, including providing BWRs for maintaining humanhealth and the health of natural ecosystems. Identifyingdesirable end results, focusing on demand-side manage-ment, and applying the sustainability criteria produces avision of California’s water system that is far more efficientand equitable and that meets basic needs as well asproviding water for extensive agricultural production. Inthis approach, meeting BWRs first coopts only a tinyfraction of total renewable supply, but sets societal prior-ities in a more equitable way than current managementapproaches.

CONCLUSIONS

Recent efforts to integrate environmental issues andconcerns with sustainable economic and social development have returned to the concept of meeting basic humanneeds first proposed nearly two decades ago. One of themost fundamental of those needs is access to clean water.This article presents the concept of a basic water require-ment (BWR) for human domestic needs and recommendsthat a BWR for drinking, basic sanitation services, humanhygiene, and food preparation be guaranteed to all hu-mans. Specifically, 50 liters per person per day of cleanwater should now be considered a fundamental humanright.

Hundreds of millions of people, especially in developingcountries, currently lack access to this BWR, resulting inenormous human suffering and tragedy. Furthermore,rapid population growth and inadequate efforts to improveaccess to water ensure that this problem will grow worsebefore it grows better. This problem should be a far higherpriority for governments, water providers, and interna-tional aid organizations than it appears to be.

In the past, long-term planning for the managementand allocation of freshwater resources has relied upontraditional projections of human demand for water, com-pared projected demand to estimates of available supply,and developed the policies and physical infrastructurenecessary to bridge the gap between the two. Absent fromtraditional water planning has been any voice for naturalecosystems, any thought that the goals, aspirations, anddesires of future generations may not be the same as thoseof the present generation, and any explicit representationof the complex interactions between land-surface pro-cesses, atmospheric behavior, the natural biota, and so-ciety, It is time for a change. A first step toward sustainablewater use would be to guarantee all humans the waterneeded to satisfy their basic needs.

ACKNOWLEDGMENTS

Thanks are due to many people who. discussed theseissues with me, including Nicki Norman, Peter Yolles,Sharad L&6, Santos Gomez, Jason Morrison, Anna Sted-ing, Bill Stewart, Penn Loh, and Pat Brenner for theircomments and thoughts. Special thanks also to GilbertWhite, Stephen McCaffrey, Sandra Postel, Malin Falken-mark, Norman Myers, Peter Rogers, and Penny Firthwho reviewed this article and offered many valuablesuggestions. Any faults or errors are my own. Fundingfor this work was provided by the Ford, Joyce Me*-Gilmore, and Horace W. Goldsmith Foundations.

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Objectives

The principal objectives of the International Water Resources Association are:

. to advance water resources planning, development, management, administration, science, technology, research.and education on an international level;

* to establish an internntional forum for planners, administrators, managers, scientists, engineers, educators,and others who are concerned with water resources; and

- to encourage coordination and support of international programs in the field of water resources. includingcooperation with the United Nations and its agencies, and other international and national organizations, inactivities of common interest.

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