United States Census, 1940 in Clairton, Allegheny County, Pennsylvania: Head/Husband "Walter Mann," wife "Alma Mann," and children "Delma, Walter, William, and Edgar Mann."
United States Census, 1930 in Clairton, Allegheny County, Pennsylvania: Head/Husband "Walter Mann," wife "Alma Mann," and children "Robert, Delma, Walter, William, and Edgar Mann."
United States Census, 1920 in Huntingdon County, Pennsylvania: Head/Husband "Walter Mann," wife "Alma Mann," and children "Robert, Delma, and Walter Mann."
Alma's last maiden name / LNAB may have been "McCartney"
(Found during cursory search on FamilySearch.com)