| 1 William Street, Trethomas, Caerphilly | Freehold | 80 m² | £75,000 (2013) |
| 2, William Street, Trethomas, Caerphilly | Freehold | 72 m² | £122,000 (2019) |
| 4 William Street, Trethomas, Caerphilly | Freehold | 79 m² | £132,000 (2026) |
| 6 William Street, Trethomas, Caerphilly | Freehold | 80 m² | £154,000 (2025) |
| 7 William Street, Trethomas, Caerphilly | Freehold | 88 m² | £140,000 (2025) |
| 8, William Street, Trethomas, Caerphilly | Freehold | 82 m² | £118,500 (2018) |
| 9 William Street, Trethomas, Caerphilly | Freehold | 81 m² | £161,000 (2022) |
| 12, William Street, Trethomas, Caerphilly | Freehold | 75 m² | £32,000 (1996) |
| 13, William Street, Trethomas, Caerphilly | Freehold | 83 m² | £160,000 (2024) |
| 14 William Street, Trethomas, Caerphilly | - | 75 m² | - |
| 16 William Street, Trethomas, Caerphilly | Freehold | 85 m² | £79,000 (2011) |
| 17, William Street, Trethomas, Caerphilly | Freehold | 107 m² | £175,000 (2024) |
| 19 William Street, Trethomas, Caerphilly | Freehold | 87 m² | £37,950 (1999) |
| 20, William Street, Trethomas, Caerphilly | Freehold | 30 m² | £73,000 (2017) |
| 23, William Street, Trethomas, Caerphilly | Freehold | 93 m² | £95,000 (2011) |
| 25, William Street, Trethomas, Caerphilly | Freehold | 85 m² | £108,000 (2015) |
| 26, William Street, Trethomas, Caerphilly | Freehold | 84 m² | £205,000 (2025) |
| 29, William Street, Trethomas, Caerphilly | Freehold | 77 m² | £100,000 (2015) |
| 33 William Street, Trethomas, Caerphilly | Freehold | 90 m² | £85,000 (2003) |
| 35, William Street, Trethomas, Caerphilly | Freehold | 81 m² | £155,000 (2022) |
| 37, William Street, Trethomas, Caerphilly | Freehold | 82 m² | £115,000 (2020) |
| 41, William Street, Trethomas, Caerphilly | Freehold | 84 m² | £157,000 (2024) |
| 43, William Street, Trethomas, Caerphilly | Freehold | 79 m² | £41,500 (2000) |
| 45, William Street, Trethomas, Caerphilly | - | 88 m² | - |
| 47 William Street, Trethomas, Caerphilly | Freehold | 80 m² | £23,000 (1998) |
| 49 William Street, Trethomas, Caerphilly | Freehold | 97 m² | £153,000 (2023) |