Oneproblemwiththesesourcesisthatthedeepwateralsohasahigherlevelofsaltthanshalloweraquifers.Thismeansthatsomewellsmayevenneedtoundergodesalinationafterextraction,thusincreasingthecost.Researchfromtheexhaustivestudyofgroundwaterfromover950drillinglogshasjustbeenpublished.Newestimatesofthewaterreservesnowgoupto2,700billioncubicmetersoffreshwater.Whatmayhappenwhendeepaquifersareusedaswatersources?