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No official flood warning is active nearby and the closest river stations are within normal ranges.
Updated 2026-10-10 00:05:21 UTC · Official GOV.UK warnings · Flood preparation & help guide
Welwyn is a village and civil parish in Hertfordshire, England. The parish also includes the nearby villages and settlements of Digswell, Mardley Heath and Oaklands. The village is sometimes referred to as Old Welwyn or Welwyn Village, to distinguish it from the much newer and larger settlement of Welwyn Garden City, about a mile to the south. Welwyn Garden City residents often refer to their town as Welwyn, causing them to call the village by the name of Old Welwyn to make a distinction. Residents of the village usually refer to it as Welwyn, or sometimes Welwyn Village to make a distinction.
Towns and villages near Welwyn with a page of their own: the homes in a flood risk area there, the nearest river gauges, and recorded floods.
Place names: Contains OS data © Crown copyright and database rights 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Contains National Statistics data © Crown copyright and database right 2026. Licensed under the Open Government Licence v3.0.
The nearest watercourse on the river map is the River Mimram, about 10 m from the middle of Welwyn's gauges. It flows into the River Lea (River Lee) about 13 km downstream.
A gauge downstream shows water that has already passed this point; one upstream sees it first. Distances along the river are from the point on the River Mimram nearest the middle of Welwyn's gauges. From Ordnance Survey’s river map (OS Open Rivers), which leaves out small streams, ditches and culverts, so a nearer one may exist. This describes where water goes on the map; it says nothing about flooding at any address. Contains OS data © Crown copyright and database rights 2026.
Welwyn is monitored by 1 Environment Agency river level station on the River Mimram, in Hertfordshire. Water levels are updated every 15 minutes, providing real-time flood monitoring for the area.
The River Mimram is monitored by 1 station (Fulling Mill). Each station records water levels continuously, with data synced to FloodRadar every 5 minutes.
There are 8 Environment Agency flood warning areas within 10km of Welwyn. When the EA issues a flood warning for any of these areas, it will appear on this page. These include: The River Mimram at Welwyn including Welwyn Garden City and Digswell; The River Mimram at Whitwell, Welwyn, Tewin, Hertingfordbury and Hertford; The River Mimram at Whitwell including Codicote; The Stevenage Brook at Stevenage including Hooks Cross.
There is 1 storm overflow within 5km of Welwyn. None of the 1 with a reporting monitor is currently discharging. Enable "Sewage" on the map above to see their locations.
It has its own page of live status and past discharges:
If flooding is forecast in Welwyn, call Floodline on 0345 988 1188 for the latest information. Move valuables upstairs, turn off gas and electricity if safe to do so, and avoid walking or driving through flood water. Sign up for flood warnings on any station page above to receive email alerts when water levels rise. For emergency numbers, a preparation checklist and insurance guidance, see our flood help & preparation guide.
Welwyn gets about 671 mm of rain a year on average (wettest month November, 68 mm; driest March, 39 mm). That is 42% drier than the UK as a whole, which averages 1,163 mm a year. See the rain gauges →
A thirty-year average for the area, not a forecast and not a flood risk on its own. Source: Met Office HadUK-Grid 1991–2020 (5 km grid), 0.5 km away. Average rainfall: HadUK-Grid v1.3.2, Met Office. Contains public sector information licensed under the Open Government Licence v3.0.
Floods whose mapped extent (EA Recorded Flood Outlines) reached within ~5 km of the town centre — most recent first. These are records of mapped extents, not a full list of floods. See them on the map →
Records, not floods: no outline on the record is not evidence a place has not flooded.
Current verdict: Normal. No official flood warning is active nearby and the closest river stations are within normal ranges.
Welwyn has river level monitoring on River Mimram — 1 monitoring station in total.
Use the GOV.UK Check for Flooding service (check-for-flooding.service.gov.uk) or call Floodline on 0345 988 1188 (24 hours). You can also set up free FloodRadar email or browser alerts from any station page above.
Follow official advice: move valuables and vehicles to safety, never walk or drive through flood water, turn off gas and electricity if safe, and check on vulnerable neighbours. See our flood preparation guide at floodradar.co.uk/flood-help.
Yes — the Environment Agency's Recorded Flood Outlines dataset shows 4 recorded flood extents around the town centre since 1703, most recently in 2007. That is a count of mapped extents, not of separate floods. Records, not floods: no outline on the record is not evidence a place has not flooded. See the flood history link below.
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