Maganin sharar ruwa wani tsari ne da ake amfani da shi don kawar da gurɓataccen ruwa daga ruwan datti da kuma mayar da shi gurɓataccen ruwa wanda za'a iya mayar da shi cikin zagayowar ruwa . Da zarar an dawo da sake zagayowar ruwa, ƙazanta yana haifar da tasiri mai karɓuwa akan yanayi ko kuma an sake yin amfani da shi don dalilai daban-daban (wanda ake kira reclamation ruwa ). Tsarin jiyya yana faruwa a cikin injin tsabtace ruwa. Akwai nau'ikan ruwan sha da yawa waɗanda ake kula da su ta hanyar da ta dace ta hanyar sarrafa ruwan sha. Ga ruwan sharar gida (wanda kuma ake kira da ruwan sha na birni ko najasa ), ana kiran wurin sarrafa najasa wurin sarrafa najasa . Don ruwan sharar masana'antu, jiyya ko dai yana faruwa a cikin wani wurin sarrafa ruwan sharar masana'antu daban, ko kuma a cikin injin sarrafa najasa (yawanci bayan wani nau'i na riga-kafi). Sauran nau'ikan masana'antar sarrafa ruwan datti sun haɗa da masana'antar sarrafa ruwan sha da aikin gona da masana'antar sarrafa shara leach.