FloodRadar
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FloodRadar
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Get notified about London Colney — tick as many as you like, they all share the notify settings below.
Each one is saved as its own alert — pause or remove them individually any time.
Not an emergency service — if in danger call 999. Alerts rely on EA/SEPA/NRW data and are best-efforts. Terms
Geographic coordinates may reflect the access point for the gauge, and not the precise location in the watercourse that it is taking readings from.
Gauges connected to this river, and others nearby. A distance “by river” follows the river on the map; any other is in a straight line.
Distances by river: OS Open Rivers. Contains OS data © Crown copyright and database rights 2026.
Storm overflows whose water reaches this gauge on the mapped river network, nearest first by distance along the river. The status is each water company's monitor: it says whether an overflow is discharging, not how much or what it contains.
1 storm overflow is traced upstream of this gauge, the nearest 11.9 km away along the river. 0 report discharging now, 1 reports not discharging.
These are the water companies' monitor statuses; a spill does not by itself explain a change in the gauge level. River connections and distances are traced on OS Open Rivers (edition 2026-04), which leaves out many small channels. Sewage & storm overflows →
Contains OS data © Crown copyright and database rights 2026.
Loading rainfall and weather data...
In a typical year this gauge reaches its typical high of 1.85 m on about 1 day. This year so far: 0 days.
Counted from each day's highest reading. Days with missing or implausible readings are left out.
Official Environment Agency warnings issued since 2009 for the 11 flood areas linked to this gauge (nearest 0.6 km away).
Most recent flood warning: 19 Jul 2025 — Radlett and Borehamwood Brooks at Borehamwood
| Year | Warnings | Alerts |
|---|---|---|
| 2026 | 0 | 14 |
| 2025 | 1 | 7 |
| 2024 | 0 | 22 |
| 2023 | 0 | 11 |
| 2022 | 0 | 5 |
| 2021 | 1 | 8 |
| 2020 | 0 | 11 |
| 2019 | 0 | 6 |
| 2018 | 0 | 4 |
| 2017 | 0 | 5 |
| 2016 | 0 | 7 |
| 2015 | 0 | 6 |
| 2014 | 6 | 9 |
| 2013 | 0 | 6 |
| 2012 | 1 | 10 |
| 2011 | 0 | 1 |
| 2010 | 0 | 2 |
| 2009 | 2 | 2 |
Warnings apply to a whole flood area, not necessarily this exact spot. Years before 2006 aren't covered by the EA's historic record. See also the London Colney flood history.
Flood warnings and alerts are issued for whole areas. These are the 11 areas linked to this gauge, nearest first.
The current level is 1.14m, which is within the typical range of 0.94 to 1.85m. Flooding is unlikely at this level.
Based on the most recent readings, the level is currently rising slightly. The chart above shows the last 12 hours of measurements by default (up to 7 days), updated roughly every 15 minutes.
The typical range at this station is 0.94m to 1.85m, based on Environment Agency historical data. Levels above 1.85m are higher than usually seen and may indicate a flood risk.
Readings are supplied by the Environment Agency gauge. FloodRadar checks for updates roughly every 15 minutes; the timestamp above shows how recent the latest available reading is.
Free live river-level widget — ideal for parish councils, angling clubs and local sites. Updates automatically.
Postcodes within 5 km with properties in the Environment Agency’s rivers-and-sea flood-risk bands:
FloodRadar helper · beta