Born in Two Rivers, Wis., Dallmann moved to New Braunfels in 1945 and in 1960 formed the New Braunfels Aquatic Club. He worked as a volunteer coach in the area for more than 50 years and almost as long as an official at local, state, national and international levels. Dallmann introduced automatic timing to Texas and to the Texas Amateur Athletic Federation and he originated, organized, and staged the first major coaching clinic in Texas at Trinity University. He started the swim team at both New Braunfels High School and Canyon High School, coaching three high school all-Americans and seven world and American record holders. As a swimmer, Dallmann medaled at the first World Masters Games in 1985 and the first FINA World Masters Swimming Championships in 1986. He set Masters world records and was named a national top ten Masters swimmer.