Ukukhetha amanzi akhuselekileyo kwifomyula yomntwana? Esi sikhokelo sithelekisa impompo, indawo yokugcina abantwana, kunye namanzi ahluziweyo. Kucetyiswa isixhobo sokucoca amanzi esikumgangatho ophezulu (umz., inkqubo ye-RO) ukususa ngokufanelekileyo izinto ezingcolisayo ezifana neesinyithi ezinzima kunye neekhemikhali, ukuqinisekisa ukhuseleko lweentsana.