悪水[akusui] undrinkable water
井戸水[idomizu] well water
一衣帯水[ichiitaisui] (being separated only by a) narrow strip of water
一水[issui] current (of water)
溢水[issui] inundation

飲水量[insuiryou] amount of drinking
飲料水[inryousui] drinking water
烏の行水[karasunogyouzui] quick bath
雲水[unsui] itinerant priest
塩化水素[enkasuiso] hydrogen chloride

井泉[seisen] (water) well
黄泉[kousen] underground spring
温泉[onsen] spa
九泉[kyuusen] hades
源泉[gensen] source

古泉学[kosengaku] numismatics
鉱泉[kousen] mineral spring
泉貨紙[senkashi] reclaimed paper
泉水[sensui] fountain