Montgomery Waste Water Treatment Works
Storm overflow run by Hafren Dyfrdwy.
"Not discharging" means the company's monitor reports no discharge right now — not that the water is clean. The feed publishes status only; no discharge volume is measured.
Year by year
Hafren Dyfrdwy's annual Event Duration Monitoring return to Natural Resources Wales (12/24-hour spill count), as compiled by The Rivers Trust.
"No data" means the monitor was not working or not required to report that year — not zero.
Discharges we have recorded
54 discharge periods since 1 Jan 2025. 54 of them come from Hafren Dyfrdwy's own event-duration-monitoring records (published by the company, Jan 2025 – Dec 2025); this overflow has no live feed, so nothing after that log is held. The official annual count is the figure to quote.
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48 min
-
1 h 52 min
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48 min
-
33 min
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3 h 32 min
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1 h 12 min
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9 h 20 min
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40 min
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4 h 20 min
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2 h 8 min
Show 30 earlier (of 54)
| Started | Ended | Discharge time |
|---|---|---|
| 3 h 0 min | ||
| 1 h 6 min | ||
| 1 h 18 min | ||
| 2 h 18 min | ||
| 6 h 34 min | ||
| 34 min | ||
| 10 min | ||
| 2 h 38 min | ||
| 1 h 21 min | ||
| 38 min | ||
| 34 min | ||
| 3 h 30 min | ||
| 2 h 44 min | ||
| 19 min | ||
| 9 min | ||
| 20 min | ||
| 16 min | ||
| 43 min | ||
| 14 min | ||
| 6 min | ||
| 32 min | ||
| 3 h 19 min | ||
| 40 min | ||
| 16 min | ||
| 2 min | ||
| 1 h 42 min | ||
| 18 min | ||
| 26 min | ||
| 4 h 23 min | ||
| 2 d 22 h |
The year figures above use the EA's 12/24-hour counting method, so they are comparable with the official figures; the monitor log's 130 raw blocks were merged into 54 continuous discharge periods (gaps under 15 min joined).
Rain nearby last 30 days
Nearest live rain gauge: Rainfall gauge nr Sarn, 7.1 km away. Brown shading = when this overflow was discharging; ▼ = a discharge start.
Overflow shading is a timing match, not proof of cause — heavy rain and spills share a trigger. Times come from the water company’s event-duration monitor (site status only; no discharge volume is published).
Where it is
Concerned about this overflow?
Report pollution you can see or smell to the regulator straight away; the company handles complaints about the overflow itself.
Spill-event history: © Hafren Dyfrdwy, published on Stream (data.streamwaterdata.co.uk) under CC BY 4.0. Annual figures: The Rivers Trust EDM compilation, © Hafren Dyfrdwy, Open Government Licence. Times are shown in UK local time. FloodRadar republishes the monitor's status; it does not measure discharges itself.