Get notified about Ewell — tick as many as you like, they all share the notify settings below.
Alert me when (tick one or more)
⤴Unusual rise — FloodRadar+Top 1% rise rate for this gauge.
Height for "Above a height"
Drag the line on the chart, or type a value:mASD
Quick pick:
You'll be notified when this gauge is rising more than 0.10 m/hr — a sign of rapidly increasing water levels.
You'll be notified when a new storm-overflow (sewage) discharge starts within ~3 km of this gauge, based on the water companies' near-real-time feeds.
Notify by (tick one or more)
Your browser will ask permission, then you'll get a notification even when FloodRadar isn't open.
On iPhone: tap Share → Add to Home Screen first, then open it from there and set the alert. Show me how
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
Current Level
0.097 mASD
▬ Steady
24h Max
0.115 mASD
24h Min
0.097 mASD
Typical Range
0.03 - 1.04
mASD
Highest Recorded
2.21 mASD
9 Feb 2014
Since Nov 2012
Current level is 4% of this
🚽Sewage overflows nearby
Recent Water Levels
🌍 floodradar.co.uk
1 day
EA forecast (official)
Prediction V2
Prediction Eris
Nimbus beta
Experimental model fusing soil moisture, river flow, groundwater and catchment
character. The shaded band is its 10–90% range, widened so that about 80% of recent outcomes fall inside it.
Under evaluation — not yet promoted, so treat as a second opinion.
River Flow
90 days
Daily mean discharge (m³/s) with the daily min–max band, from the EA Hydrology API. Flow is the volume of water passing the gauge — often a more direct flood signal than level.
Ewell GS (3350THF) — flow at this site
7 days
A separate gauge 7 m from this one at the same site, shown here for context.
Its readings are its own and are never merged with this page's.
Flow Data: Daily mean flow (m³/s) to 6 Oct (2 days behind — the EA publishes each day's mean a day or two after it ends; unchecked, provisional)via EA Hydrology
None of the storm overflows FloodRadar holds is traced upstream of this gauge on the mapped river network. That is not the same as none: the map leaves out many small streams and culverts, so an overflow it cannot place may still drain here, and not every company publishes every overflow. Those nearby are listed below.
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 · 5.5 km away in a straight line · no mapped watercourse close enough to be sure
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 →
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 Ewell flood history.
Flood areas linked to this gauge
Flood warnings and alerts are issued for whole areas. These are the 8 areas linked to this gauge, nearest first.
🌊 Urban & flashyHeavily 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
0.88
groundwater-fed — slow & steady
Avg Annual Rainfall
700 mm/yr
1991–2020 · -1% since 1941–70
Urban Extent
37%
heavily urbanised
Highest Daily Mean Flow
0.247 m³/s
17 May 2001 · daily mean, not the instantaneous peak
Flow-Duration Curve
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 3%Grassland 30%Urban 66%
About this gauge
Rectangular flume; stage-discharge relation confirmed by c/m gaugings.
More detail
The catchment
A largely suburban catchment developed mostly on Chalk (dip-slope of North Downs). Mean runoff suggests that topographical catchment greatly exceeds the contributing area.
The station
Rectangular flume; Modular. Overfall u/s. Frequently vandalised. Station downgraded in 2010 to level only.
How it measures flow
Grounding of float (stilling well floor corresponds to throat level of flume) can affect low flow accuracy. Debris on u/s grill can influence levels.
Timing, not cause. Gauges can move together simply because the same rain fell on both.
Frequently asked questions
Is the Hogsmill River at Ewell flooding today?
The current level is 0.10m, which is within the typical range of 0.03 to 1.04m. Flooding is unlikely at this level.
Is the river level rising or falling at Ewell?
Based on the most recent readings, the level is currently steady. The chart above shows the last 12 hours of measurements by default (up to 7 days), updated roughly every 15 minutes.
What is a normal level for the Hogsmill River at Ewell?
The typical range at this station is 0.03m to 1.04m, based on Environment Agency historical data. Levels above 1.04m 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.
Embed this gauge on your website
Free live river-level widget — ideal for parish councils, angling clubs and local sites. Updates automatically.
Preview
📮 Flood risk by postcode near this gauge
Postcodes within 5 km with properties in the Environment Agency’s rivers-and-sea flood-risk bands:
FloodRadar
Log inCreate free account