Tadayuki was adopted by Tadachika MIZUNO and inherited his territory of 2,030 koku in 1674 and served as tsukaiban (a person responsible for orders and patrol in a battlefield) and shinbangashira (person in charge of guarding the shogun and inspecting arms).
一族の水野忠近の養子となり、延宝2年（1674年）にその領地2030石を相続し、使番、新番頭を歴任する。