| Watertown Township | 1990 | Census 1990 | Single-Family Detached | 417 |
| Watertown Township | 2000 | Census 2000 | Single-Family Detached | 462 |
| Watertown Township | 2010 | Estimates 2010 | Single-Family Detached | 488 |
| Watertown Township | 2020 | Estimates 2020 | Single-Family Detached | 470 |
| Watertown Township | 2023 | Estimates 2023 | Single-Family Detached | 479 |
| Watertown Township | 1990 | Census 1990 | Townhomes (single-family attached) | 2 |
| Watertown Township | 2000 | Census 2000 | Townhomes (single-family attached) | 0 |
| Watertown Township | 2010 | Estimates 2010 | Townhomes (single-family attached) | 0 |
| Watertown Township | 2020 | Estimates 2020 | Townhomes (single-family attached) | 0 |
| Watertown Township | 2023 | Estimates 2023 | Townhomes (single-family attached) | 0 |
| Watertown Township | 1990 | Census 1990 | Duplex, triplex and quad | 7 |
| Watertown Township | 2000 | Census 2000 | Duplex, triplex and quad | 4 |
| Watertown Township | 2010 | Estimates 2010 | Duplex, triplex and quad | 3 |
| Watertown Township | 2020 | Estimates 2020 | Duplex, triplex and quad | 12 |
| Watertown Township | 2023 | Estimates 2023 | Duplex, triplex and quad | 12 |
| Watertown Township | 1990 | Census 1990 | Multifamily (5 units or more) | 0 |
| Watertown Township | 2000 | Census 2000 | Multifamily (5 units or more) | 2 |
| Watertown Township | 2010 | Estimates 2010 | Multifamily (5 units or more) | 0 |
| Watertown Township | 2020 | Estimates 2020 | Multifamily (5 units or more) | 0 |
| Watertown Township | 2023 | Estimates 2023 | Multifamily (5 units or more) | 0 |
| Watertown Township | 1990 | Census 1990 | Manufactured Home | 14 |
| Watertown Township | 2000 | Census 2000 | Manufactured Home | 9 |
| Watertown Township | 2010 | Estimates 2010 | Manufactured Home | 4 |
| Watertown Township | 2020 | Estimates 2020 | Manufactured Home | 0 |
| Watertown Township | 2023 | Estimates 2023 | Manufactured Home | 0 |
| Watertown Township | 1990 | Census 1990 | Other (Boat, RV, etc.) | 8 |
| Watertown Township | 2000 | Census 2000 | Other (Boat, RV, etc.) | 0 |
| Watertown Township | 2010 | Estimates 2010 | Other (Boat, RV, etc.) | 0 |
| Watertown Township | 2020 | Estimates 2020 | Other (Boat, RV, etc.) | 0 |
| Watertown Township | 2023 | Estimates 2023 | Other (Boat, RV, etc.) | 0 |
| Watertown Township | 2020 | Estimates 2020 | Accessory Dwelling Unit | 0 |
| Watertown Township | 2023 | Estimates 2023 | Accessory Dwelling Unit | 0 |