Stations are listed from source to mouth as the water flows, traced on the river map (OS Open Rivers) and the Environment Agency’s own links between its gauges. A distance “by river” is along the river, and is shown only where the map traces the path.
Streams and rivers with a gauge whose water joins the Bollin above one of its gauges, from the source down. Named streams without a gauge that have a page here are listed at the end.
Named streams on the river map that flow into the Bollin and have no gauge of their own. Each has a page with what is known about it: the next gauge downstream, and any storm overflows or water-sampling points placed on it.
Birkin Brook (joins about 3.0 km above Bollington Mill)
41 storm overflows are traced upstream of Bollington Mill, the Bollin’s lowest gauge on the river map: on the Bollin itself, on its gauged tributaries, and on smaller streams that join above there.
0 report discharging now
39 not discharging
2 offline or silent: 0 monitor offline, 2 status unknown, 0 no live feed
Official figures for 2025, for the overflows traced upstream of Bollington Mill: 1,465 spills over 7,836 hours in total, across all 41.
Each overflow is listed in the stretch above the first gauge its water reaches, from the source down, as on the Gauges tab. A stretch of the Bollin includes the smaller streams that join it there. Every overflow traced is listed here, each stretch in full. Back to the short lists →
Between Old Mill Lane and Prestbury7 overflows
Waters Green (Dams Valley) CSONot discharging United Utilities · into River Bollin · 4.9 km by river above Prestbury · 2025: 5 spills, 1.8 h
Banbury Close CSONot discharging United Utilities · into Shoresclough Brook · 4.4 km by river above Prestbury · 2025: 5 spills, 2.2 h
Hibel Road CSO 27075Not discharging United Utilities · into River Bollin · 3.8 km by river above Prestbury · 2025: 18 spills, 56 h
CSO At 18/20 Beech Farm DriveNot discharging United Utilities · into River Bollin · 3.6 km by river above Prestbury · 2025: 66 spills, 120 h
Beech Bridge South CSONot discharging United Utilities · into River Bollin · 3.5 km by river above Prestbury · 2025: 1 spill, 0.1 h
Westminster Road CSONot discharging United Utilities · into River Bollin · 3.1 km by river above Prestbury · 2025: 61 spills, 95 h
Cartmel Close CSONot discharging United Utilities · into River Bollin · 2.3 km by river above Prestbury · 2025: 9 spills, 3.2 h
Between Prestbury and Wilmslow2 overflows
Macclesfield WwTWNot discharging United Utilities · into River Bollin · 8.4 km by river above Wilmslow · 2025: 56 spills, 374 h
Wilmslow Park South CSONot discharging United Utilities · into River Bollin · 410 m by river above Wilmslow · 2025: 2 spills, 9.9 h
Between Wilmslow and Bollington Mill23 overflows
Chancel Lane CSO 271i4Not discharging United Utilities · into River Bollin · 21.7 km by river above Bollington Mill · 2025: 45 spills, 94 h
Opp River St CSO (273by)Not discharging United Utilities · into River Bollin · 21.6 km by river above Bollington Mill · 2025: 3 spills, 7.2 h
Hawthorn Lane CSONot discharging United Utilities · into Clvrt'd Trib Of River Bollin · 21.5 km by river above Bollington Mill · 2025: 9 spills, 5.4 h
Reeman Court Manhole H4 CSO 272nyNot discharging United Utilities · into River Dean · 21.0 km by river above Bollington Mill · 2025: 9 spills, 48 h
The Carrs Combined Sewer OverflowNot discharging United Utilities · into River Bollin · 20.9 km by river above Bollington Mill · 2025: 2 spills, 8.4 h
Fulshaw Cross CSO 271u4Not discharging United Utilities · into Whitehall Brook Via Sws · 20.5 km by river above Bollington Mill · 2025: 37 spills, 69 h · reaches the river through a sewer, so where it enters is approximate
Wilmslow STWNot discharging United Utilities · into River Dean · 20.4 km by river above Bollington Mill · 2025: 71 spills, 703 h
Wilmslow STWNot discharging United Utilities · into River Dean · 20.4 km by river above Bollington Mill · 2025: 51 spills, 224 h
Quarry Bank Mill CSO 272m4Not discharging United Utilities · into Tributary Of River Bollin · 18.8 km by river above Bollington Mill · 2025: 15 spills, 61 h
Sandle Bridge Ww Network PSNot discharging United Utilities · into Pedley Brook · 18.7 km by river above Bollington Mill · 2025: 7 spills, 53 h
Alderley Edge WwTW AldyeNot discharging United Utilities · into Whitehall Brook · 18.2 km by river above Bollington Mill · 2025: 91 spills, 908 h
Town Lane CSONot discharging United Utilities · into Mobberley Brook Trib Rv Bollin · 12.5 km by river above Bollington Mill · 2025: 101 spills, 835 h
St Johns Wood CSO 272s9Not discharging United Utilities · into Birkin Brook Via Sws · 12.5 km by river above Bollington Mill · 2025: 39 spills, 98 h · reaches the river through a sewer, so where it enters is approximate
Mobberley Rd CSONot discharging United Utilities · into Birkin Brook · 12.2 km by river above Bollington Mill · 2025: 2 spills, 2.6 h
Knutsford WwTWNot discharging United Utilities · into Birkin Brook · 11.8 km by river above Bollington Mill · 2025: 82 spills, 575 h
Mobberley WwTWNot discharging United Utilities · into Mobberley Brook · 11.6 km by river above Bollington Mill · 2025: 61 spills, 148 h
Mobberley WwTWNot discharging United Utilities · into Mobberley Brook · 11.6 km by river above Bollington Mill · 2025: 70 spills, 839 h
Barrow Lane CSO (451g7)Not discharging United Utilities · into Trib Of River Bollin · 9.0 km by river above Bollington Mill · 2025: 52 spills, 71 h
Park Road Arthog Road CSO 452lsNot discharging United Utilities · into River Bollin · 7.3 km by river above Bollington Mill · 2025: 74 spills, 203 h
Hale Storm Tanks & Pumping StationNot discharging United Utilities · into River Bollin · 7.1 km by river above Bollington Mill · 2025: 68 spills, 162 h
Hale Storm Tanks & Pumping StationNot discharging United Utilities · into River Bollin · 7.1 km by river above Bollington Mill · 2025: 61 spills, 835 h
Bowdon Wastewater Treatment WorksStatus unknown United Utilities · into River Bollin · 3.2 km by river above Bollington Mill · 2025: 61 spills, 605 h
Pool Bank Farm Bowdon CSO 452l6Not discharging United Utilities · into River Bollin · 3.2 km by river above Bollington Mill · 2025: 71 spills, 286 h
Dean, above Stanneylandsjoins the Bollin above Bollington Mill9 overflows
Palmerston Street CSOStatus unknown United Utilities · into Harrop Brook · 18.4 km by river above Stanneylands · 2025: 0 spills, 0 h
Palmerston St Shrigley Rd 272kzNot discharging United Utilities · into Harrop Brook · 18.4 km by river above Stanneylands · 2025: 23 spills, 17 h
Allen St/Lord St CSONot discharging United Utilities · into River Dean · 18.3 km by river above Stanneylands · 2025: 2 spills, 1.3 h
Water Street CSONot discharging United Utilities · into River Dean · 17.9 km by river above Stanneylands · 2025: 1 spill, 12 h
Adlington Road CSO (271a4)Not discharging United Utilities · into River Dean · 17.4 km by river above Stanneylands · 2025: 7 spills, 14 h
20 Adlington Road CSONot discharging United Utilities · into River Dean · 17.4 km by river above Stanneylands · 2025: 8 spills, 9.2 h
River Bank CSONot discharging United Utilities · into River Dean · 16.8 km by river above Stanneylands · 2025: 69 spills, 145 h
Dean Road CSO 278a2Not discharging United Utilities · into River Dean · 2.6 km by river above Stanneylands · 2025: 2 spills, 1.0 h
Rear Of Knowle HouseNot discharging United Utilities · into Trib River Dean · 990 m by river above Stanneylands · 2025: 48 spills, 137 h
Near these gauges, connection not known
Within 3 km of one of the Bollin’s gauges in a straight line, but the river map cannot say whether their water reaches it.
Bollin Walk CSO 27074Not discharging United Utilities · into Whitfield Brook · 410 m from Wilmslow in a straight line · its recorded watercourse is not the one mapped beside it · 2025: 21 spills, 42 h
Dunham Massey STWNot discharging United Utilities · into River Bollin · 570 m from Bollington Mill in a straight line · its water cannot be followed on the map · 2025: 43 spills, 238 h
Dunham Massey Outfall CSO (451ss)Not discharging United Utilities · into River Bollin Via Sws · 570 m from Bollington Mill in a straight line · its water cannot be followed on the map · 2025: 43 spills, 167 h
Roewoods Outfall SewerNot discharging United Utilities · into Un-Named Trib Of River Bollin · 1.9 km from Prestbury in a straight line · no mapped watercourse close enough to be sure · 2025: 31 spills, 43 h
Sagars Rd CSO (279df)Not discharging United Utilities · into Dean Brook · 2.1 km from Wilmslow in a straight line · no mapped watercourse close enough to be sure · 2025: 0 spills, 0 h
Dated samples taken by the Environment Agency, not live readings. Results are published days to months after the sample is taken, and many points are sampled only a few times a year, or have not been sampled for years.
63 sampling points on the River Bollin and the streams that join it above Bollington Mill, and below it. 14 have a sample from the last 12 months; 19 have any sample banked.
Sampled most recently, anywhere on the Bollin and its streams:
Mobberley Brook downstream of Mobberley EtwMobberley Brook · 11 km above Bollington MillLast sampled 14 Sep 2026 · 24 days agoOxygen 92.5%Temp 18.1 °CpH 7.95Ammonia below 0.03 mg/l
Birkin Brook above confluence BollinBirkin Brook · 3.2 km above Bollington MillLast sampled 11 Sep 2026 · 27 days agoOxygen 91% Aug 2026Temp 15.4 °CpH 7.76Ammonia 0.038 mg/l
River Bollin Warburton Bridge HeatleyRiver Bollin · 4.3 km below the lowest gaugeLast sampled 17 Aug 2026 · 52 days agoOxygen 84.9%Temp 17.1 °CpH 7.76Ammonia 0.1 mg/l
England's samples only. Each count opens the list of those points, nearest first, with the date of each one’s latest sample (the gauge’s “Upstream of here” list).
FloodRadar does not grade these results: there is no overall score, and official river classifications are a separate dataset. A sample taken downstream of an overflow does not by itself show where anything in it came from. River connections and distances are traced on OS Open Rivers (edition 2026-04), which leaves out many small channels.
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