Ko te mata o te ruma ngingiha he 50% te rahi ake i etahi atu hua rite, he iti ake te pāmahana o roto o te ruma ngingiha, he rite tonu te tohatoha;
Ko te hongere wai huri noa i te ruuma ngingiha e mau ana i te hoahoa hurihuri, e karo ana i te ahua o te wera maroke i te wa e whakamahia ana te whakawhiti;
Ko te nui o te wai o te tinana whakawhiti wera he 22% te nui atu i etahi atu hua rite, a ka tino piki ake te waahanga whakawhiti o te awa wai;
Ko te whakamaaramatanga o te hongere wai ka whakatikahia e te whaihanga rorohiko, ka iti ake te parenga wai me te iti ake o te paatete;
Ko te hoahoa ahurei o te riu riu i roto i te hongere wai ka whakanui ake i te waahi o te whakawhiti wera, ka whakarei ake i te awe o te rere ohorere, me te whakakaha i te whakawhiti wera o roto.