Isifudumezi sokuntywilisela sifudumeza amanzi ngqo ngaphakathi kuwo.Apha, kukho into yokufudumeza entywiliselwe emanzini, kwaye umbane onamandla ugqithiswa kuwo obangela ukuba kushushu amanzi adibane nawo.
Isifudumezi-manzi sokuntywiliselwa sisifudumezi-manzi sombane esihlala ngaphakathi kwi-cylinder yamanzi ashushu.Isebenza kancinci njengeketile, isebenzisa isifudumezi sombane (esikhangeleka ngathi yintsimbi yentsimbi okanye ikhoyili) ukufudumeza amanzi ajikelezileyo.
Izifudumezi zokuntywiliselwa ze-WNH ziyilelwe ikakhulu ukuntywiliselwa kulwelo olunjengamanzi, i-oyile, izinyibilikisi kunye nezinyibiliko zenkqubo, imathiriyeli etyhidiweyo kunye nomoya kunye neegesi.Ngokuvelisa bonke ubushushu ngaphakathi kolwelo okanye inkqubo, ezi zifudumezi zisebenza ngokumalunga ne-100 ekhulwini lombane.Ezi zifudumezi zisebenza ngeendlela ezahlukeneyo zisenokwakheka kwaye zibunjwe kwiijometri ezahlukeneyo zokufudumeza okukhazimlayo kunye nezicelo zokufudumeza umphezulu wonxibelelwano.