Is Hertfordshire at risk of flooding?

Hertfordshire has 88 designated flood areas monitored by the Environment Agency, giving it a High risk rating. It ranks #21 out of 152 English counties for flood risk.

How many flood warning areas are in Hertfordshire?

There are 88 flood warning and alert areas in Hertfordshire, monitored by 0 Environment Agency stations across 29 rivers.

Which rivers flood in Hertfordshire?

The main rivers in Hertfordshire include Ash, Beane, Beverley Brook, Beverley Brook, Pyl Brook, East Pyl Brook, Groundwater and 24 others. These rivers have monitoring stations tracking water levels in real time.

Do I need flood insurance in Hertfordshire?

If your property is in or near one of Hertfordshire's 88 flood areas, flood insurance is strongly recommended. The government's Flood Re scheme helps make flood insurance affordable for at-risk properties.

How can I check flood risk for my postcode?

Use the Environment Agency's flood risk checker or our postcode lookup tool to check the flood risk for your specific address. You can also browse Hertfordshire's flood areas on this page.

What was the worst flood in Hertfordshire?

Hertfordshire has experienced significant flooding events over the years. Check the Environment Agency's historical flood data and our UK Flood History guide for details on major events.

Flood Risk in Hertfordshire

East of England

Flood Areas

Stations

Rivers

Risk Level

High

#21 of 152 counties

Flood Areas in Hertfordshire

88 designated flood warning and alert areas

Name	River / Sea	Type
River Thames at Thames Ditton Island including Boyle Farm Island	River Thames	Warning
River Thames at Thames Ditton Island including Boyle Farm Island	River Thames	Alert
River Thames from Shepperton to West and East Molesey including Hamm Court, Walton-on-Thames and Sunbury	River Thames	Alert
River Ivel from Langford to Blunham, including the rivers Purwell, Hiz, Flit and Hit	River Ivel	Alert
Trinity Marsh Ditch at Waltham Cross	Trinity Marsh Ditch, Small River Lee	Warning
The Radlett Brook at Radlett	Radlett Brook	Warning
The Upper River Colne and Radlett Brook at Colney Heath, London Colney, Borehamwood and Radlett	River Colne	Alert
The River Crane at Hillingdon, Southall, Cranford, Feltham and Twickenham	River Crane	Alert
River Lee at Luton, Harpenden including Wheathampstead and East Hyde	River Lee	Alert
Beverley Brook at Barnes, London Boroughs of Richmond upon Thames and Wandsworth	Beverley Brook	Warning
Beverley Brook area, including the Pyl Brook, in the London Boroughs of Merton, Sutton, Kingston upon Thames, Richmond upon Thames and Wandsworth	Beverley Brook, Pyl Brook, East Pyl Brook	Alert
River Thames from the River Brent to the River Crane including East Isleworth and Syon Park	River Thames	Warning
River Thames including areas in the boroughs of Kensington & Chelsea, Hammersmith & Fulham, Ealing and Hounslow	River Thames	Alert
River Thames including areas in the boroughs of Wandsworth and Richmond-upon-Thames	River Thames	Alert
River Thames from Raven's Ait to Teddington Weir including, Raven's Ait, the Hogsmill River below the university Knights Park Campus, both Kingston...	River Thames	Warning
River Thames from Hampton and Thames Ditton to Teddington including Hampton Wick and Kingston-upon-Thames	River Thames	Alert
River Hogsmill area from Ewell to Kingston upon Thames, including the Surbiton Stream in Surbiton and the Green Lane Stream between Ewell and Epsom	Hogsmill	Alert
River Thames at Thames Ditton including Ditton Field and Ditton Reach	River Thames	Warning
River Thames at Teddington including Broom Road and Lower Teddington Road	River Thames	Warning
River Thames flood area near Hertfordshire	River Thames	Warning
The River Ash in Hertfordshire including Furneux Pelham, Little Hadham, Much Hadham and Wareside	Ash	Alert
River Thames at East and West Molesey including Hurst Park, Buckingham Avenue and the Royal Mews area	River Thames	Warning
The River Ver at Markyate, Redbourn and St. Albans	River Ver	Alert
River Thames from Putney Bridge to Mortlake High Street East including Barnes	River Thames	Warning
The River Bulbourne at Boxmoor, Hemel Hempstead	River Bulbourne	Warning
The River Gade and Bulbourne at Boxmoor, Hemel Hempstead, Frogmore End, Kings Langley and Croxley	River Gade; River Bulbourne	Alert
The River Colne at Colney Heath including North Mymms	River Colne	Warning
Beverley Brook at Worcester Park, including Motspur Park, London Boroughs of Kingston upon Thames and Sutton	Beverley Brook	Warning
River Thames at Kingston-upon-Thames town including, central Kingston, the area around Canbury Gardens and Albany Park Road	River Thames	Warning
River Thames at Trowlock Island including the Royal Canoe Club	River Thames	Alert
The River Colne at London Colney including Colney Street and Broad Colney	River Colne	Warning
The River Gade at Hemel Hempstead	River Gade	Warning
The River Gade at Kings Langley and Croxley, including Abbots Langley	River Gade	Warning
The River Mimram from Tewin to Hertford including Hertingfordbury	Mimram	Warning
The River Mimram at Whitwell, Welwyn, Tewin, Hertingfordbury and Hertford	Mimram	Alert
The Rivers Rib and Quin at Chipping, Buntingford, Braughing, Standon, Barwick, Wadesmill and Hertford	River Rib, River Quin	Alert
Beverley Brook at West Barnes, London Boroughs of Kingston upon Thames and Merton	Beverley Brook	Warning
The Radlett and Borehamwood Brooks at Borehamwood	Radlett Brook	Warning
The River Ash at Little Hadham, Hadham Ford, Much Hadham, Widford and Wareside	Ash	Warning
Beverley Brook at Raynes Park Including Beverley Way and Malden Golf Course, London Boroughs of Kingston upon Thames and Merton	Beverley Brook	Warning
River Thames from the Hogarth Lane Roundabout to the River Brent including South Chiswick, Grove Park, Strand-on-the-Green and Brentford	River Thames	Warning
The River Rib at Wadesmill to Hertford	Rib	Warning
The River Beane at Walkern including Holbrook	Beane	Warning
The River Beane catchment including the Stevenage Brook and the Dane End Tributary	River Beane, Dane End Tributary, Stevenage Brook	Alert
River Thames flood area near Hertfordshire	River Thames	Warning
The River Ash at Furneux Pelham including Clapgate	Ash	Warning
The Mimmshall Brook at Warrengate Road including Water End	Mimmshall Brook	Warning
The Mimmshall Brook at Warrengate Road including South Mimms, Potters Bar, Brookmans Park and Welham Green	Mimmshall Brook	Alert
The Middle River Colne at Watford and Rickmansworth including Carpenders Park	River Colne	Alert
River Thames at Walton-on-Thames including Desborough Island, Walton Bridge and Elmbridge Leisure Centre	River Thames	Warning
The Stevenage Brook at Stevenage including Hooks Cross	Stevenage Brook	Warning
River Lee at Harpenden and Wheathampstead including East Hyde	River Lee	Warning
The River Beane at Hertford	Beane	Warning
River Hogsmill at Ewell Court, Ruxley and Old Malden, London Borough of Kingston upon Thames and Epsom and Ewell	Hogsmill	Warning
The River Quin at Braughing	Quin	Warning
River Rhee from Guilden Morden to Haslingfield	River Rhee	Alert
The River Rib at Buntingford to Barwick including Standon	Rib	Warning
The Dane End tributary at Dane End including Sacombe	Beane	Warning
The River Ver at St Albans including Sopwell, Park Street and Frogmore	River Ver	Warning
The River Colne at Watford including Bushey	River Colne	Warning
The River Crane at Cranford and Feltham including North Feltham	River Crane	Warning
River Thames at Hampton and Hampton Wick including Hampton Court, properties on the Barge Walk, Hampton Court Palace Golf Club and Hampton Court Road	River Thames	Warning
The River Mimram at Welwyn including Welwyn Garden City and Digswell	Mimram	Warning
The River Gade at Frogmore End including Apsley and Bennets End, Hemel Hempstead	River Gade	Warning
River Thames riverside from Putney Bridge to Teddington Weir	River Thames	Alert
The Rags Brook at Flamstead End to Cheshunt	Rags Brook	Warning
Beverley Brook at Wimbledon Common and Richmond Park including Kingston Vale and Robin Hood Gate and Roehampton, London Boroughs of Kingston upon T...	Beverley Brook	Warning
The Tidal River Crane at Twickenham	River Crane	Alert
River Lee from Lemsford to Hertford including Welwyn Garden City, Hatfield and Mill Green	River Lee	Warning
River Hogsmill at Kingston, London Borough of Kingston upon Thames	Hogsmill	Warning
River Thames at Trowlock Island including the Royal Canoe Club	River Thames	Warning
The River Ver at Markyate including Flamstead, Harpenden	River Ver	Warning
The Small River Lee at Cheshunt including, Turnford, Holdbrook and Enfield Lock	Small River Lee, River Lee	Warning
The River Crane at Twickenham including Cole Park	River Crane	Warning
The River Mimram at Whitwell including Codicote	Mimram	Warning
Areas at risk of groundwater flooding in Kimpton and Lilley Bottom, including Lye Hill, Whiteway and Claggy Bottom	Groundwater	Alert
Areas at risk of groundwater flooding around Flamstead, including Trowley Bottom and Lower Sawpit Wood	Groundwater	Alert
The Tidal River Crane at Isleworth	River Crane	Warning
The River Ver at Redbourn including Redbournbury	River Ver	Warning
River Thames flood area near Hertfordshire	River Thames	Warning
The River Beane at Watton-at-Stone to Waterford including Stapleford	Beane	Warning
The River Chess at Loudwater, Rickmansworth	River Chess	Warning
The River Colne at Rickmansworth including Batchworth, Money Hill and Maple Cross	River Colne	Warning
River Thames from Richmond Bridge to Teddington Weir including West Petersham and Ham Lands	River Thames	Warning
River Thames from the River Crane to Teddington Weir including St. Margaret's, Eel Pie Island, Strawberry Hill and East Teddington	River Thames	Warning
River Thames flood area near Hertfordshire	River Thames	Warning
Surbiton Stream at Berrylands, Alexandra, Surbiton Hill, Tolworth and Hook Rise, London Borough of Kingston upon Thames	Surbiton	Warning
River Ivel flood area near Hertfordshire	River Ivel	Warning

Monitoring Stations

0 Environment Agency monitoring stations

Rivers in Hertfordshire

AshBeaneBeverley BrookBeverley Brook, Pyl Brook, East Pyl BrookGroundwaterHogsmillMimmshall BrookMimramQuinRadlett BrookRags BrookRibRiver Beane, Dane End Tributary, Stevenage BrookRiver BulbourneRiver ChessRiver ColneRiver CraneRiver GadeRiver Gade; River BulbourneRiver IvelRiver LeeRiver RheeRiver Rib, River QuinRiver ThamesRiver VerSmall River Lee, River LeeStevenage BrookSurbitonTrinity Marsh Ditch, Small River Lee

Flood Insurance Warning for Hertfordshire

Hertfordshire has 88 designated flood areas and a high flood risk rating. If you live in this area, check your buildings and contents insurance covers flood damage. Homes in high-risk areas may face higher premiums or require specialist cover.

Flood Insurance Guide →Planning & Flood Risk →