Any person who shall place or cause to be placed within any watershed from which any city or municipal corporation of any adjoining state obtains its water supply, any substance which either by itself or in connection with other matter will corrupt, pollute or impair the quality of said water supply, or the owner of any dead animal who shall knowingly leave or cause to be left the carcass or any portion thereof within any such watershed in such condition as to in any way corrupt or pollute such water supply shall be deemed guilty of a misdemeanor and upon conviction shall be punished by fine in any sum not exceeding five hundred dollars.
RCW 70.54.030