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Water Level Easing
Easing — down from 0.20 at 16:15, now 0.18
0.18

Chertsey Lock

Thames ⚙ Structure
Thames from Hurley to Teddington catchment • Chertsey • Surrey • ID: 2902TH • Level
(24m ago) • 4 readings/hr • 169 views

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Get notified about Chertsey Lock — tick as many as you like, they all share the notify settings below.

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Not an emergency service — if in danger call 999. Alerts rely on EA/SEPA/NRW data and are best-efforts. Terms

Current Level
0.177 mASD
▼ Easing
24h Max
0.238 mASD
24h Min
0.162 mASD
Typical Range
0.13 - 0.40
mASD
Highest Recorded
1.32 mASD
EA official record
1.21 in our data (since Nov 2012)
Current level is 13% of this
🚽 Sewage overflows nearby

Recent Water Levels

🌍 floodradar.co.uk
1 day

Flood predictions aren't generated for lock / structure gauges — their levels are driven by gate operation, not by catchment rainfall, so the forecast models would have no skill here.

Recent Readings

Falling · -1 cm over 6h
10 Oct 01:30 ▬ steady 0.177 mASD
10 Oct 01:15 ▼ -0.1 cm 0.177 mASD
10 Oct 01:00 ▼ -0.1 cm 0.178 mASD
10 Oct 00:45 ▼ -0.1 cm 0.179 mASD
10 Oct 00:30 ▼ -0.2 cm 0.180 mASD
10 Oct 00:15 ▼ -0.1 cm 0.182 mASD
10 Oct 00:00 ▼ -0.1 cm 0.183 mASD
09 Oct 23:45 ▼ -0.1 cm 0.184 mASD
09 Oct 23:30 ▼ -0.3 cm 0.185 mASD
09 Oct 22:30 ▼ -0.1 cm 0.188 mASD
09 Oct 22:15 ▬ steady 0.189 mASD
09 Oct 22:00 ▼ -0.1 cm 0.189 mASD
09 Oct 21:45 ▼ -0.1 cm 0.190 mASD
09 Oct 21:30 ▬ steady 0.191 mASD
09 Oct 21:15 ▬ steady 0.191 mASD
09 Oct 21:00 ▼ -0.1 cm 0.191 mASD
09 Oct 20:45 ▲ +0.1 cm 0.192 mASD
09 Oct 20:30 ▲ +0.2 cm 0.191 mASD
09 Oct 20:15 ▬ steady 0.189 mASD
09 Oct 20:00 0.189 mASD

Station Details

  • Monitoring Station: Chertsey Lock
  • Watercourse: River Thames
  • Nearest Town: Chertsey
  • County: Surrey
  • Coordinates: 51°23'26"N 0°29'11"W (51.390617, -0.486370)
  • Open in: Google Maps · Apple Maps (opens your maps app)
  • Date Opened: 1 Jan 1985
  • Status: Active
  • Station Type: River level station (multi-sensor)
Technical details: references, datum, range, flow archive
  • Station Reference: 2902TH
  • RLOI id: 7215 (the EA's check-for-flooding station id)
  • EA Gauge ID: 2902TH-level-stage-i-15_min-mASD
  • Parameter: Level
  • Unit: mASD
  • Typical rise rate: 5 cm/hr (p95 sustained over 90 days)
  • Typical data delay: ~22 min (measured reading→publication lag)
  • Tidal: No
  • Lock / structure: ⚙ Yes — lock, weir, sluice or pump
  • Catchment Area: Thames from Hurley to Teddington
  • Typical Range: 0.131 – 0.402 mASD
  • EA Cross-check: 2.63 mASD (EA at 10 Oct 01:15)

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

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.

118 storm overflows are traced upstream of this gauge, the nearest 13.8 km away along the river. 0 report discharging now, 115 report not discharging, and for 3 the monitor is offline or has not reported, so their status is not known.

💧
Thames Water · into Thames · 13.8 km upstream along the river
34 spills · 333 hours in 2025
Not discharging now · last
💧
Thames Water · into Colne Brook · 20.2 km upstream along the river
0 spills · 0 hours in 2025
Not discharging now · last
💧
Thames Water · into Roundmoor Ditch · 24.5 km upstream along the river
14 spills · 246 hours in 2025
No live feed for this overflow
💧
Thames Water · into Misbourne · 29.3 km upstream along the river
88 spills · 1,605 hours in 2025
Not discharging now · last
💧
Thames Water · into River Colne · 32.8 km upstream along the river
35 spills · 455 hours in 2025
Not discharging now · last
💧
Thames Water · into Misbourne · 39.8 km upstream along the river
13 spills · 167 hours in 2025
Not discharging now · last
💧
Thames Water · into River Thames · 40.1 km upstream along the river
2 spills · 10 hours in 2025
Not discharging now · last
💧
Thames Water · into The Cut · 40.8 km upstream along the river
19 spills · 215 hours in 2025
Not discharging now · last
Placed on the river by its position alone.

110 more further upstream, up to 219.1 km away along the river.

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 Rive Ditch · 4.7 km away in a straight line · its water cannot be followed on the map
1 spill · 1 hours in 2025
Not discharging now · last

2 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...

Flood history near this gauge

Official Environment Agency warnings issued since 2012 for the 29 flood areas linked to this gauge (nearest 0.1 km away).

9severe warnings 88flood warnings 177flood alerts

Most recent flood warning: 6 Feb 2026 — Areas of Chertsey closest to the Chertsey Bourne

Year by year
YearSevereWarningsAlerts
2026 0 1 33
2025 0 0 11
2024 0 19 17
2023 0 1 19
2022 0 0 8
2021 0 2 9
2020 0 1 13
2019 0 1 8
2018 0 0 7
2017 0 0 1
2016 0 0 14
2015 0 0 3
2014 9 46 6
2013 0 8 15
2012 0 9 13

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 Chertsey flood history.

Flood areas linked to this gauge

Flood warnings and alerts are issued for whole areas. These are the 29 areas linked to this gauge, nearest first.

Show 21 more

Frequently asked questions

Is the River Thames at Chertsey Lock flooding today?

The current level is 0.18m, which is within the typical range of 0.13 to 0.40m. Flooding is unlikely at this level.

Is the river level rising or falling at Chertsey Lock?

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. 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 River Thames at Chertsey Lock?

The typical range at this station is 0.13m to 0.40m, based on Environment Agency historical data. Levels above 0.40m 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 →