וְכִֽי־יִטְהַ֤ר הַזָּב֙ מִזּוֹב֔וֹ וְסָ֨פַר ל֜וֹ שִׁבְעַ֥ת יָמִ֛ים לְטָהֳרָת֖וֹ וְכִבֶּ֣ס בְּגָדָ֑יו וְרָחַ֧ץ בְּשָׂר֛וֹ בְּמַ֥יִם חַיִּ֖ים וְטָהֵֽר׃
E quando colui che ha un problema viene ripulito dal suo problema, allora dovrà contare per se stesso sette giorni per la sua pulizia e lavarsi i vestiti; e bagnerà la sua carne nell'acqua corrente e sarà pulito.
Mishnah Mikvaot
Superior to them are "smitten waters" which can purify even when flowing [on the ground]. Superior to them are "living waters" for in them there is immersion for zavim and sprinkling for metzoraim, and they are valid for the preparation of the hatat waters.
Mishnah Mikvaot
[Water from] a spring which is made to pass over into a trough becomes invalid. If it was made to pass over the edge in any quantity, [what is] outside [the trough] is valid, for [the water of] a spring purifies however little its quantity. If it is made to pass over into a pool and then is stopped, the pool counts as a mikveh. If it is made to flow again, it is invalid for zavim and for those with skin disease and for the preparation of the hatat waters until it is known that the former [water] is gone.