River Ash
Joins the Lee between Waterhall and Hoddesdon, Rye Bridge, no more than 8.1 km by river above Hoddesdon, Rye Bridge. Nearest the Lee: Mardock Normal; 2 more gauges further up.
Live levels from 8 monitoring stations across Central Bedfordshire, Greater London, Hertfordshire, Luton, updated every 15 minutes.
| Station | Level now | Status | ||
|---|---|---|---|---|
| Luton, Toddington Roadstructure | -0.03 mASD 1h ago | Low | ||
| 4.1 km by river | ||||
| Luton, Stockingstone Road | 0.03 mASD 1h ago | Normal | ||
| 7.3 km by river | ||||
| Luton East Hyde | 1.09 mASD 1h ago | Normal | ||
| 3.3 km by river | ||||
| Harpenden | 0.79 mASD 1h ago | Normal | ||
| 23.2 km by river | ||||
| Waterhall | 0.13 mASD 1h ago | Normal | ||
| 15.6 km by river | ||||
| Hoddesdon, Rye Bridge | 2.85 mASD 1h ago | Normal | ||
| Station | Level now | Status | ||
|---|---|---|---|---|
| Continues from the section above: downstream below Hoddesdon, Rye Bridge, distance by river not measured | ||||
| Walthamstow, Low Hallstructure | 0.03 mASD 1h ago | Normal | ||
| downstream, distance by river not measured | ||||
| Lea Bridge | 5.86 mASD 1h ago | Normal | ||
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.
Contains OS data © Crown copyright and database rights 2026.
Streams and rivers with a gauge whose water joins the Lee above one of its gauges, from the source down. The river map knows where gauges are, not every stream, so a tributary without a gauge is not listed here.
Each tributary’s water passes the gauge it joins above and every gauge below it on the Lee, and none of the gauges above where it joins. For each, the gauge nearest the Lee is shown; its own page lists the rest.
Joins the Lee between Waterhall and Hoddesdon, Rye Bridge, no more than 8.1 km by river above Hoddesdon, Rye Bridge. Nearest the Lee: Mardock Normal; 2 more gauges further up.
Joins the Lee above Hoddesdon, Rye Bridge, no more than 5.8 km by river above Hoddesdon, Rye Bridge. Nearest the Lee: Tumbling Bay Weir Normal; 10 more gauges further up. Gauged streams joining it: River Beane, River Mimram and River Rib.
Joins the Lee above Lea Bridge, no more than 7.1 km by river above Lea Bridge. Nearest the Lee: Edmonton, Silver Street Normal; 3 more gauges further up.
Joins the Lee above Lea Bridge, no more than 8.4 km by river above Lea Bridge. Nearest the Lee: Edmonton Green Normal; 1 more gauge further up. Gauged streams joining it: Salmon Brook.
Joins the Lee above Lea Bridge, no more than 12.8 km by river above Lea Bridge. Nearest the Lee: Enfield, Ordance Road Normal; 3 more gauges further up. Gauged streams joining it: Rags Brook and Trinity Marsh Ditch.
Joins the Lee above Lea Bridge, no more than 13.1 km by river above Lea Bridge. Nearest the Lee: Enfield, Albany Park Normal.
Below Lea Bridge, its water next reaches Charlton, a gauge on Thames Tideway, 12.4 km by river downstream.
Tributaries and where they join are traced on the river map (OS Open Rivers, edition 2026-04) and the Environment Agency’s links between its gauges. The map holds distances between gauges, not the junctions themselves, so a junction is placed between two gauges, and no further up than the tributary’s own lowest gauge. Contains OS data © Crown copyright and database rights 2026.
33 storm overflows are traced upstream of Lea Bridge, the Lee’s lowest gauge on the river map: on the Lee itself, on its gauged tributaries, and on smaller streams that join above there.
Official figures for 2025, for the overflows traced upstream of Lea Bridge: 103 spills over 548 hours in total, across all 33.
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 Lee includes the smaller streams that join it there. Where a stretch or a tributary has more than 4, the 3 discharging now or nearest its gauge are listed, the rest are counted, and every one is in that gauge’s “Upstream of here” list. Show every overflow in every stretch →
and 15 more: show all 18 overflows on this stretch → All above Luton East Hyde, nearest first →
Within 3 km of one of the Lee’s gauges in a straight line, but the river map cannot say whether their water reaches it.
5 more near these gauges whose connection is not known.
A status is the water company’s own monitor: it says whether an overflow is discharging, never how much or why, and a spill does not by itself explain a change in a river level. A status older than two hours is shown as unknown. Annual figures are the official returns: 12/24-hour spills for England and Wales, overflow events for Scotland (Scottish Water counts differently, so the two cannot be compared). “No data” means the monitor produced no usable data that year, not zero. Overflows are placed on OS Open Rivers (edition 2026-04), which leaves out many small channels: an overflow the map cannot place may still drain here. Contains OS data © Crown copyright and database rights 2026. Sewage in Britain’s rivers →
Live status: © Thames Water storm overflow activity data, licensed under CC BY 4.0. Annual figures for England: Environment Agency Event Duration Monitoring return, © Environment Agency copyright and/or database right, Open Government Licence v3.0.
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.
40 sampling points on the River Lee and the streams that join it above Lea Bridge, and below it. 33 have a sample from the last 12 months; 36 have any sample banked. Listed from the source down, grouped by the next gauge each one's water reaches.
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Lee above Luton Hoo Lakes | River Lea | 3.0 km | 3 Aug 2026 · 2 months ago | Oxygen 10.4%Temp 18.3 °CpH 7.6Ammonia 8 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Lee above Luton (East Hyde) sewage treatment works | River Lea | 3.0 km | No sample published 1 Oct 2023 – 7 Oct 2026 | |
| Lee at East Hyde Road Bridge | River Lea | 1.9 km | 7 Aug 2026 · 2 months ago | Oxygen 92.1%Temp 20.9 °CpH 7.75Ammonia 0.034 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Rib at Chapel Green Common | River Rib | 6.5 km | 11 Sep 2026 · 27 days ago | Oxygen 101.8% Mar 2026Temp 7.4 °C Mar 2026pH 8.23 Mar 2026Conductivity 593 µS/cm Mar 2026 |
| Rib at Chipping - Buntingford | River Rib | 3.7 km | 10 Dec 2025 · 10 months ago | Oxygen 92.9%Temp 8.8 °CpH 8.09Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Tributary of Beane Stocking Hill | unnamed stream | 5.4 km | 10 Aug 2026 · 59 days ago | Oxygen 93.6% Feb 2026Temp 4.8 °C Feb 2026pH 8.48 Feb 2026Ammonia below 0.03 mg/l Feb 2026 |
| Beane at Luffenhall | River Beane | 3.1 km | 7 Sep 2026 · 31 days ago | Oxygen 93.4% Mar 2026Temp 8.8 °C Mar 2026pH 8 Mar 2026Conductivity 576 µS/cm Mar 2026 |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| At Kimpton Mill Ford | River Mimram | 4.2 km | 13 Aug 2026 · 56 days ago | Oxygen 100.2%Temp 17.9 °CpH 8.11Ammonia below 0.03 mg/l |
| Mimram at Codicote Bottom | River Mimram | 3.2 km | 4 Sep 2026 · 34 days ago | Oxygen 91.4%Temp 16.5 °CpH 7.76Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Mimram at Tewin Bury Farm | River Mimram | 1.9 km | 1 Dec 2023 · 2.9 years ago | Oxygen 95.1%Temp 5.8 °CpH 7.94Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Rib at Westmill | River Rib | 17 km | 4 Sep 2026 · 34 days ago | Oxygen 73.2%Temp 15.1 °CpH 7.12Ammonia below 0.03 mg/l |
| Rib at A10 New Bridge | River Rib | 15 km | 1 Sep 2026 · 37 days ago | Oxygen 90%Temp 13.7 °CpH 7.83Ammonia below 0.03 mg/l |
| Quin at Braughing Bridge | River Quin | 14 km | 1 Sep 2026 · 37 days ago | Oxygen 92.7%Temp 13.8 °CpH 7.63Ammonia below 0.03 mg/l |
| Rib at Standon | River Rib | 11 km | 1 Sep 2026 · 37 days ago | Oxygen 79.2%Temp 13.4 °CpH 7.75Ammonia below 0.03 mg/l |
| Rib at Old Church Lane | River Rib | 1.0 km | 2 Dec 2024 · 22 months ago | Oxygen 93.4%Temp 9.7 °CpH 7.92Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Lee at Wheathampstead | River Lea | 18 km | 7 Aug 2026 · 2 months ago | Oxygen 92.2%Temp 18.8 °CpH 7.98Ammonia below 0.03 mg/l |
| Lee at Stanborough | River Lea | 9.7 km | No sample published 1 Oct 2023 – 7 Oct 2026 | |
| Lee at Holwell Bridge | River Lea | 3.3 km | 6 Aug 2026 · 2 months ago | Oxygen 94.4%Temp 18.9 °CpH 7.97Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Stevenage Brook at Frogmore Hall | Stevenage Brook | 12 km | 4 Sep 2026 · 34 days ago | Oxygen 57.8%Temp 18.2 °CpH 7.37Ammonia 0.8 mg/l |
| Beane at Watton at Stone | River Beane | 10 km | 4 Sep 2026 · 34 days ago | Oxygen 71.9%Temp 17.6 °CpH 7.5Ammonia 0.47 mg/l |
| Beane at Beane Road, Hertford | River Beane | 1.1 km | 1 Sep 2026 · 37 days ago | Oxygen 74.5%Temp 14.7 °CpH 7.53Ammonia 0.051 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Ash at Bridge North of Widford | River Ash | 4.9 km | 21 Sep 2026 · 17 days ago | Oxygen 94.3%Temp 12.5 °CpH 7.9Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Mimram at Panshanger | River Mimram | 10 km | 1 Sep 2026 · 37 days ago | Oxygen 14.5%Temp 14.5 °CpH 7.57Ammonia 0.036 mg/l |
| Lee at Waterhall | River Lea | 9.9 km | 6 Aug 2026 · 2 months ago | Oxygen 101.1%Temp 18.1 °CpH 8.01Ammonia below 0.03 mg/l |
| Lee at Hertford Castle | River Lea | 5.2 km | 21 Sep 2026 · 17 days ago | Oxygen 97%Temp 13.7 °CpH 7.93Ammonia below 0.03 mg/l |
| Rib at Bengeo Hall | River Rib | 3.8 km | 1 Sep 2026 · 37 days ago | Oxygen 74.8%Temp 16.2 °CpH 7.81Ammonia below 0.03 mg/l |
| Lea tributary downstream of Bengeo Bridge | River Rib | 3.6 km | 1 Sep 2026 · 37 days ago | Oxygen 77.4%Temp 16 °CpH 7.83Ammonia below 0.03 mg/l |
| Lee Nav at Kings Meads | River Lea | 2.9 km | 2 Dec 2024 · 22 months ago | Oxygen 95.9%Temp 10.3 °CpH 7.78Ammonia below 0.03 mg/l |
| Lee above Ware Lock (for New Gauge Intake) | River Lea | 1.3 km | 7 Aug 2026 · 2 months ago | Oxygen 150.9%Temp 18.5 °CpH 8.05Ammonia below 0.03 mg/l |
| Lee Navigation at Saracens Head gauging station | River Lea | 0.5 km | 14 Jan 2026 · 9 months ago | Oxygen 94.4%Temp 6.5 °CpH 7.95Conductivity 764 µS/cm |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Ash at Easneye | River Ash | 4.2 km | 1 Sep 2026 · 37 days ago | Oxygen 79.6%Temp 14.5 °CpH 7.86Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Turkey Brook tributary below Coopers Lane | unnamed stream | 12 km | 3 Aug 2026 · 2 months ago | Oxygen 90.7% Apr 2026Temp 7.7 °C Apr 2026pH 7.94 Apr 2026Ammonia below 0.03 mg/l Apr 2026 |
| Cuffley Brook at Whitewebbs Golf Course | Cuffley Brook | 3.5 km | 9 Sep 2026 · 29 days ago | Oxygen 63.9%Temp 13.6 °CpH 7.64Ammonia below 0.03 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Small River Lee below Windmill Lane- Small River Lee | Small River Lee | 4.1 km | 1 Sep 2026 · 37 days ago | Oxygen 35.3%Temp 15.4 °CpH 7.55Ammonia 0.39 mg/l |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Turkey Brook above Small River Lee | Turkey Brook | 12 km | 2 Sep 2026 · 36 days ago | Oxygen 58.4%Temp 17.4 °CpH 7.67Ammonia 0.06 mg/l |
| Small River Lee at Mollison Avenue | Small River Lee | 12 km | No sample published 1 Oct 2023 – 7 Oct 2026 | |
| Lee Nav Subsidiary B at Keides Weir | River Lea | 9.4 km | No sample published 1 Oct 2023 – 7 Oct 2026 |
| Sampling point | Watercourse (map) | Above the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Mimram at Lilley Bottom Road | River Mimram | 0.8 km | 4 Sep 2026 · 34 days ago | Oxygen 68.9% Aug 2026Temp 13.3 °C Aug 2026pH 7.5 Aug 2026Conductivity 643 µS/cm Aug 2026 |
| Sampling point | Watercourse (map) | Below the gauge | Last sample | Latest results (river water) |
|---|---|---|---|---|
| Lee above Lea Bridge Weir | River Lea | 1.0 km | 18 Sep 2026 · 20 days ago | Oxygen 85.5%Temp 19.8 °CpH 7.47Ammonia 0.083 mg/l |
| Lee at Carpenters Road | River Lea | 4.6 km | 17 Jul 2026 · 3 months ago | Oxygen 67.6%Temp 22.1 °CpH 7.57Ammonia 0.082 mg/l |
Distances are along the river to the gauge named. England's samples only.
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.
Water samples: Environment Agency Water Quality Archive, © Environment Agency and/or database right 2026, Open Government Licence v3.0.
Contains OS data © Crown copyright and database rights 2026.
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