Before he joined the landscape industry as a designer, contractor, and waterscape creator, Frank Manwarren had a long career as a firefighter for the Los Angeles City Fire Department. He was officially appointed a fireman on September 23, 1946, and retired on May 1, 1970. He was known as being a "courageous" public servant and after leaving its professional ranks, remained close to his colleagues - once referred to as a "regular" at the Los Angeles Fire Department Museum.

 
Frank's other passion - creating outdoor water features - evolved while he was still with LAFD as he and friends constructed water sculptures and monuments. In 1961, Frank earned his general contractor's license.

Remembered in the industry as "dedicated, professional and hilarious," Frank was instrumental in the development of water rides at Astroworld Six Flags, Magic Mountain Six Flags, Six Flags over New Jersey and Opryland in Nashville, Tennessee.

Other landscape career highlights included the Japanese Pavillion at Disney World/Epcot Park and natural habitats for zoos in major US cities. Frank also counted hotels among his clients and had an enthusiasm for floral gardens. One that held a special place in his memory, and the legacy he left, is in Taipei, Republic of China, better recognized as Taiwan.

Frank was one of the team of skilled artisans, technicians, engineers, designers, landscape architects, and project managers at The Site Development Studios in Costa Mesa, California, which specialized in the design and construction of architectural fountains. The firm enjoyed proficiency in the creation of naturalistic and ornamental water features, including architectural fountains, lakes, ponds, and streams of any size or complexity. Themed environments and rockwork were also part of Frank's portfolio.