אַ֣ךְ מַעְיָ֥ן וּב֛וֹר מִקְוֵה־מַ֖יִם יִהְיֶ֣ה טָה֑וֹר וְנֹגֵ֥עַ בְּנִבְלָתָ֖ם יִטְמָֽא׃
Nevertheless a fountain or a cistern wherein is a gathering of water shall be clean; but he who toucheth their carcass shall be unclean.
Targum Jonathan on Leviticus
But fountains and cisterns, the place of the collection of running waters, shall be clean: but he who toucheth the carcase of any of those things (that may have fallen) into the water shall be unclean.