| 1930 | George B Knapp | Head | 40 | Own | White | Married | Pennsylvania | Valve & Meter Plant | Mech. Engineer | |
| Janet D Knapp | Wife | 38 | | White | Married | Pennsylvania | | | |
| George Brunette Knapp, Jr. | Son | 17 | | White | Single | New Jersey | | | |
| Robert Dixon Knapp | Son | 12 | | White | Single | Pennsylvania | | | |
| Virginia M Knapp | Daughter | 6 | | White | Single | Pennsylvania | | | |
| 1940 | George B Knapp | Head | 51 | Own | White | Married | Pennsylvania | Steel Factory | Time Study | |
| Janet D Knapp | Wife | 48 | | White | Married | Pennsylvania | | | |
| George Brunette Knapp, Jr. | Son | 27 | | White | Single | New Jersey | Gardener | Laborer | |
| Robert Dixon Knapp | Son | 22 | | White | Single | Pennsylvania | Factory | Time Study | |
| Virginia M Knapp | Daughter | 16 | | White | Single | Pennsylvania | | | |
| 1950 | George B Knapp | Head | 61 | | White | Married | Pennsylvania | Recording Instruments | Mechanical Engineer | |
| Janet D Knapp | Wife | 58 | | White | Married | Pennsylvania | | | |
| Virginia M Knapp | Daughter | 27 | | White | Never | Pennsylvania | Truck manufacturer | Secretary | |