Water Valley is not in my card file, the basis for the book I published in 1982 : "Adoption Agencies, Orphanages and Maternity Homes--An Historical Directory." Copies of my book were purchased by the Meridian Public Library (in Meridian) and the Lee County Library (in Tupelo). To make room on their book shelves, libraries may discard books.
I doubt that Water Valley is included in the special censuses of dependent children, conducted in 1923 and 1933. If you wish to do research in a library, check this out :
UNITED STATES. Census, Bureau of the. Benevolent Institutions, 1904. [Washington, D.C.: Govt. Print. Off.], 1905. 335 p. (Special Reports). A directory of 4,207 institutions (excluding 85), with their addresses and statistics: orphanages, hospitals, temporary homes for adults and children, etc. Includes a single alphabetical index to the institutions. (Charities--U.S.) (Hospitals--U.S.) (Orphanages--U.S.) (LC 06002276)
There is an implication in your query that you have seen the federal census of 1900, but you do not mention if the orphanage has a name in that census.