| 293 Preston Old Road CSO (052m0) | River Blakewater | Not Discharging | 24:00 Jan 01 1970 | 14:03 Jan 28 |
| 293 Preston Old Road CSO (052m0) | River Darwen | Not Discharging | 21:16 Jul 16 2025 | 14:03 Jan 28 |
| Accrington Road CSO | Culverted section of Knuzden Brook | Not Discharging | 09:48 Jan 27 | 14:03 Jan 28 |
| Addison Close CSO | River Blakewater a tributary of the River Darwen | Not Discharging | 10:10 Jan 27 | 14:03 Jan 28 |
| Apple Street CSO | River Blakewater | Not Discharging | 08:00 Dec 10 2025 | 14:03 Jan 28 |
| Appleby Sreett CSO | Culverted tributary of the River Blakewater, a tributary of the River Darwen | Not Discharging | 10:36 Jan 27 | 14:03 Jan 28 |
| Aqueduct Road CSO | River Darwen | Not Discharging | 14:52 Jan 27 | 14:03 Jan 28 |
| Back Queens Park Rd | Culverted Tributary of River Blakewater | Not Discharging | 02:04 Dec 15 2025 | 14:03 Jan 28 |
| Beechwood Road CSO | River Blakewater | Not Discharging | 08:18 Dec 10 2025 | 14:03 Jan 28 |
| Bolton Road Combined Sewer Overflow | River Darwen | Not Discharging | 10:04 Jan 27 | 14:03 Jan 28 |
| Brownhill Drive CSO | Culverted Tributary of River Blakewater | Not Discharging | 10:50 Jun 23 2025 | 14:03 Jan 28 |
| Cherry Tree Works Site | River Darwen | Not Discharging | 13:56 Jan 12 | 14:03 Jan 28 |
| Cumberland Street CSO | Queens Park Culvert (Tributary of River Blakewater) | Not Discharging | 08:30 Dec 10 2025 | 14:03 Jan 28 |
| Daisy Lane CSO | River Blakewater | Not Discharging | 24:00 Jan 01 1970 | 14:03 Jan 28 |
| Dickens Street CSO | Queens Park Culvert (tributary of River Blakewater) | Not Discharging | 13:56 Dec 13 2025 | 14:03 Jan 28 |
| Dukes Brow CSO | River Blakewater | Not Discharging | 20:50 Jan 06 | 14:03 Jan 28 |
| Fielden Street CSO | River Blakewater, a tributary of the River Darwen | Not Discharging | 18:06 Dec 02 2025 | 14:03 Jan 28 |
| Gate Street CSO | Culverted tributary of River Blakewater | Not Discharging | 08:06 Dec 10 2025 | 14:03 Jan 28 |
| Gorse St Combined Sewer Overflow | River Darwen | Not Discharging | 09:49 Jan 27 | 14:03 Jan 28 |
| Great Bolton Street CSO | River Blakewater | Not Discharging | 11:06 Feb 03 2025 | 14:03 Jan 28 |
| Grimshaw Park CSO | Culverted section of an unnamed trib. of River Blakewater | Not Discharging | 20:18 Jul 22 2025 | 14:03 Jan 28 |
| Infirmary Street CSO 05050 | Leeds Liverpool Canal | Not Discharging | 02:24 Jan 01 2025 | 14:03 Jan 28 |
| Lark Hill/Brookhouse Lane CSO | Culverted tributary of River Blakewater | Not Discharging | 08:00 Dec 10 2025 | 14:03 Jan 28 |
| Lower Audley CSO | Culverted tributary of River Blakewater | Not Discharging | 09:24 Jan 27 | 14:03 Jan 28 |
| Manor Road CSO (052er) | Culverted tributary of River Blakewater via surface water surface | Not Discharging | 15:44 Sep 20 2025 | 14:03 Jan 28 |
| Merchants Landing Culvert St CSO | River Blakewater via the Culvert street culvert | Not Discharging | 13:22 Jan 26 | 14:03 Jan 28 |
| New Mill Street CSO | River Blakewater | Not Discharging | 12:50 Oct 24 2025 | 14:03 Jan 28 |
| Notre Dame Gardens CSO | River Blakewater | Not Discharging | 21:56 Sep 20 2025 | 14:03 Jan 28 |
| Philips Road CSO | River Blakewater | Not Discharging | 11:56 Jan 27 | 14:03 Jan 28 |
| Philips Road CSO (052lo) | A culverted tributary of River Blakewater via surface water sewer | Not Discharging | 12:08 Jan 28 | 14:03 Jan 28 |
| Preston New Road | Tributary of Arley Brook | Not Discharging | 10:27 Jan 27 | 14:03 Jan 28 |
| Pringle Street CSO | Culverted tributary of River Blakewater | Not Discharging | 16:00 Jul 15 2025 | 14:03 Jan 28 |
| Queens Park Road CSO | Queens Park Culvert and then to the River Blakewater via surface water sewer | Not Discharging | 10:18 Jan 27 | 14:03 Jan 28 |
| Ramsgreave Drive CSO | Culverted tributary of the River Blakewater | Not Discharging | 13:30 Jan 28 | 14:03 Jan 28 |
| Revidge Rd/Preston New Rd Sso | Trubutary of Arley Brook | Not Discharging | 01:22 Oct 14 2025 | 14:03 Jan 28 |
| Sharples Street CSO | Culverted tributary of River Darwen | Not Discharging | 18:14 Jan 27 | 14:03 Jan 28 |
| Thwaites Brewery Yard | River Blakewater | Not Discharging | 10:42 Jan 27 | 14:03 Jan 28 |
| Victoria Street CSO | Tributary of River Blakewater | Not Discharging | 20:50 Jan 06 | 14:03 Jan 28 |
| Wellington Road CSO | River Darwen | Not Discharging | 20:56 Sep 20 2025 | 14:03 Jan 28 |
| Whalley New Road CSO | River Blakewater | Not Discharging | 22:24 Jan 27 | 14:03 Jan 28 |
| Whalley Old Rd/Providence St CSO | Little Harwood Brook | Not Discharging | 09:46 Jan 13 | 14:03 Jan 28 |
| Whalley Range / Wesley Street CSO | River Blakewater | Not Discharging | 09:58 Nov 07 2025 | 14:03 Jan 28 |
| Whalley Range/Grace Street CSO | River Blakewater | Not Discharging | 16:02 Sep 20 2025 | 14:03 Jan 28 |
| Whalley Range/Millham Street CSO | River Blakewater via surface water sewer | Not Discharging | 24:52 Nov 19 2025 | 14:03 Jan 28 |
| Witton Tanks CSO | River Blakewater | Not Discharging | 10:34 Jan 27 | 14:03 Jan 28 |