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Water Level Easing
Easing — down from 0.20 at 18:00, now 0.17
0.17

Kingston Hogsmill

Hogsmill River
London catchment • Kingston Upon Thames • Greater London • ID: 3390TH • Level
(33m ago) • 4 readings/hr • 153 views

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Current Level
0.172 mASD
▼ Easing (+1cm/hr)
24h Max
0.200 mASD
24h Min
0.057 mASD
Typical Range
0.11 - 0.90
mASD
Highest Recorded
1.23 mASD
EA official record
1.23 in our data (since Nov 1985)
Current level is 14% of this
🚽 Sewage overflows nearby

Recent Water Levels

🌍 floodradar.co.uk
1 day

Recent Readings

Rising · +5 cm over 5h
09 Oct 22:30 ▲ +0.4 cm 0.172 mASD
09 Oct 22:15 ▲ +0.2 cm 0.168 mASD
09 Oct 22:00 ▼ -1 cm 0.166 mASD
09 Oct 21:45 ▲ +0.3 cm 0.179 mASD
09 Oct 21:30 ▼ -0.3 cm 0.176 mASD
09 Oct 21:15 ▬ steady 0.179 mASD
09 Oct 21:00 ▼ -0.2 cm 0.179 mASD
09 Oct 20:45 ▲ +2 cm 0.181 mASD
09 Oct 20:30 ▼ -0.7 cm 0.166 mASD
09 Oct 20:15 ▼ -2 cm 0.173 mASD
09 Oct 20:00 ▲ +0.5 cm 0.195 mASD
09 Oct 19:45 ▲ +0.4 cm 0.190 mASD
09 Oct 19:30 ▼ -0.7 cm 0.186 mASD
09 Oct 19:15 ▼ -0.7 cm 0.193 mASD
09 Oct 19:00 ▲ +1 cm 0.200 mASD
09 Oct 18:45 ▲ +3 cm 0.189 mASD
09 Oct 18:30 ▲ +0.5 cm 0.157 mASD
09 Oct 18:15 ▼ -1 cm 0.152 mASD
09 Oct 18:00 ▲ +4 cm 0.164 mASD
09 Oct 17:45 0.127 mASD

Station Details

Technical details: references, datum, range, flow archive
  • Station Reference: 3390TH
  • RLOI id: 7266 (the EA's check-for-flooding station id)
  • EA Gauge ID: 3390TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 9 cm/hr (p95 sustained over 90 days)
  • Typical data delay: ~22 min (measured reading→publication lag)
  • Tidal: No
  • Lock / structure: No
  • Catchment Area: London
  • Typical Range: 0.106 – 0.900 mASD
  • Drainage Area: 69 km² upstream of this gauge
  • Flow Data: Daily mean flow (m³/s) to 7 Oct (2 days behind — the EA publishes each day's mean a day or two after it ends; unchecked, provisional) via EA Hydrology
  • EA Cross-check: 0.17 mASD (EA at 9 Oct 22:15)
  • Flow Archive: National River Flow Archive ↗

Geographic coordinates may reflect the access point for the gauge, and not the precise location in the watercourse that it is taking readings from.

Nearby Stations

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.

Connected upstream

Connected downstream

Same river system, separate branch

Nearby

Distances by river: OS Open Rivers. Contains OS data © Crown copyright and database rights 2026.

💧 Storm overflows upstream of this gauge

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.

2 storm overflows are traced upstream of this gauge, the nearest 1.1 km away along the river. 0 report discharging now, 2 report not discharging.

💧
Thames Water · into Hogsmill River · 1.1 km upstream along the river
14 spills · 139 hours in 2025
Not discharging now · last
💧
Thames Water · into Hogsmill · 7.8 km upstream along the river
4 spills · 13 hours in 2025
Not discharging now · last

Nearby, connection not known

Within 6 km in a straight line, but the river map cannot say whether their water passes this gauge.

💧
Thames Water · into Old Pyl Ditch · 4.6 km away in a straight line · no mapped watercourse close enough to be sure
1 spill · 1 hours in 2025
Not discharging now · last
💧
Thames Water · into Tidal Thames · 5.4 km away in a straight line · discharges to the sea, an estuary or tidal water
0 spills · 0 hours in 2025
No live feed for this overflow
💧
Thames Water · into River Thames · 5.6 km away in a straight line · discharges into a tidal reach, where the water moves both ways
8 spills · 18 hours in 2024
No live feed for this overflow

7 other overflows within 6 km are downstream of this gauge or on another branch of the river network, so they are not listed.

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. Explore the sewage map →

Contains OS data © Crown copyright and database rights 2026.

Rainfall & Weather

Loading rainfall and weather data...

How often this river runs high

In a typical year this gauge reaches its typical high of 0.90 m on about 1 day. This year so far: 0 days.

2026 0 days so far
2025 0 days
2024 2 days
2023 1 day
2022 0 days
2021 3 days
2020 2 days
2019 0 days
2018 0 days
2017 1 day

Counted from each day's highest reading. Days with missing or implausible readings are left out.

Flood history near this gauge

Official Environment Agency warnings issued since 2012 for the 9 flood areas linked to this gauge (nearest 0.7 km away).

1flood warning 83flood alerts

Most recent flood warning: 25 Jul 2021 — Beverley Brook at West Barnes

Year by year
YearWarningsAlerts
2025 0 4
2024 0 5
2023 0 1
2022 0 10
2021 1 16
2020 0 5
2019 0 11
2018 0 11
2017 0 7
2016 0 4
2014 0 2
2013 0 3
2012 0 4

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 Kingston Upon Thames flood history.

Flood areas linked to this gauge

Flood warnings and alerts are issued for whole areas. These are the 9 areas linked to this gauge, nearest first.

Show 1 more

Catchment Character

🌊 Urban & flashy Heavily built-up — rain runs off hard surfaces fast, so levels can spike within hours of heavy rain.

Your catchment is all the land that drains rainfall into the river above this gauge. Its character — how steep, wet, wooded, urban or chalky that land is — decides how fast rain here turns into a rising river. A steep, bare or clay catchment is “flashy” (rises and falls quickly, floods easily); a flat, chalk or well-wooded one is slow and steady. The tiles below put numbers to that; the flow-duration curve reads left-to-right from the river’s typical high flows (Q5) down to its low flows (Q95) — a steep curve means a flashy river.

The physical character of the land that drains to this gauge, and how it shapes its flood response — from the National River Flow Archive (UKCEH).

Baseflow Index
0.60
mixed response
Avg Annual Rainfall
692 mm/yr
1991–2020 · +1% since 1941–70
Urban Extent
31%
heavily urbanised
Median Annual Flood
13.80 m³/s
QMED — typical yearly peak flow
Highest Daily Mean Flow
15.00 m³/s
15 Sep 1968 · daily mean, not the instantaneous peak
Flow-Duration Curve
mean 1.122.320.9340.5675% (high)% of days exceeded95% (low)
Daily flow (m³/s) exceeded each % of the time — a steep curve is flashy, a flat one is steady. Q5 high · Q50 median · Q95 low.
Land Cover (2023)
Woodland 9%Grassland 36%Arable 3%Urban 52%

Flow affected by: effluent returns.

Photos

Gauging-station photographs from the National River Flow Archive (UKCEH).

Photos © NRFA / UKCEH & the measuring authority — shown at web resolution. Full gallery on the NRFA ↗

About this gauge

Non-standard flume with broad-crested weir. Responsive regime but flows are influenced by water imports and sewage effluent.

More detail

The catchment

A largely urban/suburban catchment in SW London developed mainly on London Clay but headwaters are on the edge of the chalk of the North Downs.

The station

Non-standard flume with bed invert/broad crested weir, 9.1m broad situated in a short reach between u/s and d/s bends. Baffles installed on downstream face of structure for fish passage.

How it measures flow

Modular to beyond MAF. One peak flow rating applied across period of record. Rating reasonably accurate, though less so above 0.6m. Non-modular flow above this level is not well described by the current rating. Baffles installed Feb 2017 and a gauging programme was carried out by JBA in the following years. No requirement for rating adjustment was concluded.

Flow regime

Responsive regime but sewage effluent, which has increased over time, dominates the dry weather flow. Chalk headwaters contribute to baseflow during wet winters. Significant imports of water, hence unrepresentative runoff.

The flow record

Some pre-war data available; station relocated following post-war river works. Full period of record peak flow data reviewed and released in September 2020 (WINFAP Files v9).

Descriptions from the National River Flow Archive (UKCEH). NRFA station record ↗

Gauge Details

How this gauging station is built and how long it has measured (NRFA / UKCEH).

Gauge type
Gauging structure
Operating since
1956
Station datum
6.1 mAOD
Flow record
1956–2024 · 68 yrs · 99% complete
Peak-flow record
since 1956
Hydrometric area
39
Measured by
Environment Agency

Frequently asked questions

Is the Hogsmill River at Kingston Hogsmill flooding today?

The current level is 0.17m, which is within the typical range of 0.11 to 0.90m. Flooding is unlikely at this level.

Is the river level rising or falling at Kingston Hogsmill?

Based on the most recent readings, the level is currently falling slightly. The chart above shows the last 12 hours of measurements by default (up to 7 days), updated roughly every 15 minutes.

Why is the level slowly falling?

When little or no rain has fallen for a while, a river level gradually drops as the water stored in the ground and soil drains away with nothing to replace it. This is called baseflow recession and is normal in dry spells. Only about 7.6mm of rain has fallen nearby in the last 7 days, so the flow is being sustained mainly by groundwater. A gentle decline like this is expected and is not a sign of a problem — downstream gauges often recede a little faster than headwaters further upstream, and levels recover once rain returns.

What is a normal level for the Hogsmill River at Kingston Hogsmill?

The typical range at this station is 0.11m to 0.90m, based on Environment Agency historical data. Levels above 0.90m are higher than usually seen and may indicate a flood risk.

How often is this river level data updated?

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.

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📮 Flood risk by postcode near this gauge

Postcodes within 5 km with properties in the Environment Agency’s rivers-and-sea flood-risk bands:

Check any UK postcode’s flood risk →

🏠 Buying or renting around here? Get the Property Flood-Risk Report for any English postcode — official risk band, recorded floods, warning history, river behaviour and nearby storm overflows. £19 one-off. Learn more →