| 293 Preston Old Road CSO (052m0) | River Blakewater | Not Discharging | 24:00 Jan 01 1970 | 01:56 Apr 29 |
| 293 Preston Old Road CSO (052m0) | River Darwen | Not Discharging | 13:38 Mar 11 | 01:56 Apr 29 |
| Accrington Road CSO | Culverted section of Knuzden Brook | Not Discharging | 09:26 Apr 12 | 01:56 Apr 29 |
| Addison Close CSO | River Blakewater a tributary of the River Darwen | Not Discharging | 17:14 Apr 15 | 01:56 Apr 29 |
| Apple Street CSO | River Blakewater | Not Discharging | 08:00 Dec 10 2025 | 01:56 Apr 29 |
| Appleby Sreett CSO | Culverted tributary of the River Blakewater, a tributary of the River Darwen | Not Discharging | 17:18 Apr 15 | 01:56 Apr 29 |
| Aqueduct Road CSO | River Darwen | Not Discharging | 14:33 Mar 29 | 01:56 Apr 29 |
| Back Queens Park Rd | Culverted Tributary of River Blakewater | Not Discharging | 18:06 Feb 27 | 01:56 Apr 29 |
| Beechwood Road CSO | River Blakewater | Not Discharging | 17:00 Apr 15 | 01:56 Apr 29 |
| Bolton Road Combined Sewer Overflow | River Darwen | Not Discharging | 17:02 Apr 15 | 01:56 Apr 29 |
| Brownhill Drive CSO | Culverted Tributary of River Blakewater | Not Discharging | 10:50 Jun 23 2025 | 01:56 Apr 29 |
| Cherry Tree Works Site | River Darwen | Not Discharging | 17:02 Apr 15 | 01:56 Apr 29 |
| Cumberland Street CSO | Queens Park Culvert (Tributary of River Blakewater) | Not Discharging | 22:24 Mar 24 | 01:56 Apr 29 |
| Daisy Lane CSO | River Blakewater | Not Discharging | 16:16 Mar 09 | 01:56 Apr 29 |
| Dickens Street CSO | Queens Park Culvert (tributary of River Blakewater) | Not Discharging | 13:04 Mar 29 | 01:56 Apr 29 |
| Dukes Brow CSO | River Blakewater | Not Discharging | 17:00 Apr 15 | 01:56 Apr 29 |
| Fielden Street CSO | River Blakewater, a tributary of the River Darwen | Not Discharging | 18:06 Dec 02 2025 | 01:56 Apr 29 |
| Gate Street CSO | Culverted tributary of River Blakewater | Not Discharging | 18:00 Mar 24 | 01:56 Apr 29 |
| Gorse St Combined Sewer Overflow | River Darwen | Not Discharging | 12:47 Mar 29 | 01:56 Apr 29 |
| Great Bolton Street CSO | River Blakewater | Not Discharging | 11:06 Feb 03 2025 | 01:56 Apr 29 |
| Grimshaw Park CSO | Culverted section of an unnamed trib. of River Blakewater | Not Discharging | 13:17 Mar 09 | 01:56 Apr 29 |
| Infirmary Street CSO 05050 | Leeds Liverpool Canal | Not Discharging | 02:24 Jan 01 2025 | 01:56 Apr 29 |
| Lark Hill/Brookhouse Lane CSO | Culverted tributary of River Blakewater | Not Discharging | 18:30 Mar 24 | 01:56 Apr 29 |
| Lower Audley CSO | Culverted tributary of River Blakewater | Not Discharging | 13:44 Mar 29 | 01:56 Apr 29 |
| Manor Road CSO (052er) | Culverted tributary of River Blakewater via surface water surface | Not Discharging | 15:44 Sep 20 2025 | 01:56 Apr 29 |
| Merchants Landing Culvert St CSO | River Blakewater via the Culvert street culvert | Not Discharging | 19:18 Apr 28 | 01:56 Apr 29 |
| New Mill Street CSO | River Blakewater | Not Discharging | 19:24 Mar 24 | 01:56 Apr 29 |
| Notre Dame Gardens CSO | River Blakewater | Not Discharging | 12:42 Apr 13 | 01:56 Apr 29 |
| Philips Road CSO | River Blakewater | Not Discharging | 14:32 Mar 29 | 01:56 Apr 29 |
| Philips Road CSO (052lo) | A culverted tributary of River Blakewater via surface water sewer | Not Discharging | 13:36 Apr 17 | 01:56 Apr 29 |
| Preston New Road | Tributary of Arley Brook | Not Discharging | 17:22 Apr 15 | 01:56 Apr 29 |
| Pringle Street CSO | Culverted tributary of River Blakewater | Not Discharging | 16:00 Jul 15 2025 | 01:56 Apr 29 |
| Queens Park Road CSO | Queens Park Culvert and then to the River Blakewater via surface water sewer | Not Discharging | 23:02 Mar 24 | 01:56 Apr 29 |
| Ramsgreave Drive CSO | Culverted tributary of the River Blakewater | Not Discharging | 11:10 Apr 27 | 01:56 Apr 29 |
| Revidge Rd/Preston New Rd Sso | Trubutary of Arley Brook | Not Discharging | 01:22 Oct 14 2025 | 01:56 Apr 29 |
| Sharples Street CSO | Culverted tributary of River Darwen | Not Discharging | 13:42 Apr 17 | 01:56 Apr 29 |
| Thwaites Brewery Yard | River Blakewater | Not Discharging | 13:32 Mar 29 | 01:56 Apr 29 |
| Victoria Street CSO | Tributary of River Blakewater | Not Discharging | 13:26 Apr 17 | 01:56 Apr 29 |
| Wellington Road CSO | River Darwen | Not Discharging | 20:56 Sep 20 2025 | 01:56 Apr 29 |
| Whalley New Road CSO | River Blakewater | Not Discharging | 17:32 Feb 03 | 01:56 Apr 29 |
| Whalley Old Rd/Providence St CSO | Little Harwood Brook | Not Discharging | 13:32 Apr 17 | 01:56 Apr 29 |
| Whalley Range / Wesley Street CSO | River Blakewater | Not Discharging | 09:58 Nov 07 2025 | 01:56 Apr 29 |
| Whalley Range/Grace Street CSO | River Blakewater | Not Discharging | 16:02 Sep 20 2025 | 01:56 Apr 29 |
| Whalley Range/Millham Street CSO | River Blakewater via surface water sewer | Not Discharging | 24:52 Nov 19 2025 | 01:56 Apr 29 |
| Witton Tanks CSO | River Blakewater | Not Discharging | 13:26 Mar 29 | 01:56 Apr 29 |