keywordswaterfootprint liters1dayinternalwaterfootprint howmuchofthatparticularfootprintlieswithinacountryexternalwaterfootprint howmuchisrelatedtowaterinimportedproductshydrologicalcycle constantrecyclingofwaterdistributionofEarth'swater70 ofEarthiscoveredwwaterbutmostofthewaterissaltyandnotusableforhumanactivitiesthereisnosubstitutionforwaterfreshwaterisalimitedresource2.5 ofallwateronEarthisfresho007 ofEarth'sfreshwaterisconsidered economicallyavailabletopeoplewaterstresswaterstressisaconseauenceof2typesofwaterscarcityphysicalwaterscarcityresultsfrominadequateavailabilityofnaturalwaterresourcestosupplyaregion'sdemandAround1.2billionpeoplecurrentlyliveinareasofphysicalscarcityanother500millionareapproachingthissituationeconomicwaterscarcityoccurseitherduetoacountry'slackofnecessaryinfrastructuretotakewaterfromrivers aquifersanddeliverittotheirpopulationormeapopulationcan'taffordtouseanimprovedwatersourceSome1.6billionpeoplecurrentlyfacethisproblemIn2010theUNGArecognizedtherightofeveryhumantohaveaccesstosufficientwater1estimated 50toolorabout13.526.5gallonspercapitaperdayforpersonaldomesticusesThatwatermustbesafefreeofmicroorganisms chemicalcontaminantsaffordable nomorethan3 ofhouseholdincomephysicallyaccessible within1ooomofhomewcollectiontimenotexceeding30minslt ac YtT Sw ao2availabilityofsanitationservices1facilities isoftenrelated3amountofwaterusedpercapitaineachsector4e agriculturedomesticandindustrial topovertywMillennium development goals MDGspledgestoreducethenumberofpplwholiveinextremepovertyOnegoalwastoreducebyhalftheproportionofpplwoSustainableaccesstosafedrinkingwater basicsanitationAccesstosafedrinkingwaterismeasuredbymonitoringaccesstoimprovedwatersources theMDGwasabletoacheme88 globalaccessby2015