Although oil paintings dominated his artistic output, Birger Sandzén was an exceptional watercolorist – completing in excess of 500 watercolors in his lifetime. His watercolors were critically acclaimed and he maintained memberships in several important societies. He was the founder and member of the Prairie Water Color Painters. Additionally, he was a member of the American Water Color Society, the New York Water Color Club, the Philadelphia Water Color Club, and the California Water Color Society.