| Area/District | Active Postcodes |
| CH1 | 2,014 |
| CH2 | 1,027 |
| CH25 | 118 |
| CH26 | 82 |
| CH27 | 115 |
| CH28 | 46 |
| CH29 | 111 |
| CH3 | 1,310 |
| CH30 | 47 |
| CH31 | 101 |
| CH32 | 118 |
| CH33 | 77 |
| CH34 | 138 |
| CH4 | 1,135 |
| CH41 | 1,116 |
| CH42 | 804 |
| CH43 | 1,083 |
| CH44 | 909 |
| CH45 | 927 |
| CH46 | 684 |
| CH47 | 431 |
| CH48 | 624 |
| CH49 | 778 |
| CH5 | 1,424 |
| CH6 | 572 |
| CH60 | 577 |
| CH61 | 491 |
| CH62 | 969 |
| CH63 | 949 |
| CH64 | 761 |
| CH65 | 966 |
| CH66 | 1,062 |
| CH7 | 1,957 |
| CH70 | 51 |
| CH8 | 803 |
| CH88 | 26 |
| CH99 | 50 |