A na-eji valvụ usoro a eme ihe nke ukwuu n'inye mmiri na ọkpọkọ mmiri n'ihe owuwu, kemịkalụ, ọgwụ, iwu ụgbọ mmiri na ụlọ ọrụ ndị ọzọ dị ka ngwaọrụ na-agbanyụ ma na-achịkwa, yana uru nke mkpuchi abụọ na-eduga na nchekwa oghere. Nwere onwe gị ịkpọtụrụ anyị iji hazie valvụ maka ọrụ gị.