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

汽車[kisha] train (sometimes specifically a steam train)
汽車賃[kishachin] train fare
汽水[kisui] brackish water
汽船[kisen] steamship
汽笛[kiteki] steam whistle

蒸汽[jouki] steam
夜汽車[yogisha] night train
蒸汽船[joukisen] steamship
汽鑵[kikan] boiler
汽缶室[kikanshitsu] boiler room