Does HP4 flood?

Yes — parts of the HP4 district carry real flood risk: 16 of its 27 at-risk postcodes reach the Environment Agency's High likelihood band. The HP4 postcode district covers Berkhamsted Castle, Northchurch, Berkhamsted West, Berkhamsted East, close to Hemel Hempstead, Chesham, Markyate, and surrounding villages in parts of Hertfordshire and Buckinghamshire.

27 postcodes in the HP4 district appear in the Environment Agency's rivers-and-sea flood-risk dataset — worst bands: 16 high, 3 medium, 8 low. A postcode not listed here has no properties in any recorded risk band (which is good news, but never proof it cannot flood).

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Which HP4 postcodes are at risk?

Rivers and flooding history near HP4

The rivers that matter here, each monitored live on FloodRadar:

Hemel Hempstead, Old Fishery Lane on the River Bulbourne — 5.4 km away, highest on record 1.80m
Gadebridge Park on the River Gade — 6.5 km away, highest on record 0.41m
Hemel Hempstead, Two Waters Road on the River Bulbourne — 7.1 km away, highest on record 1.19m
Chesham on the River Chess — 7.5 km away, highest on record 0.88m

14 official flood warnings and alerts have been raised within ~10 km of the district's centre since 2006 (1 at warning level or above), most recently 23 September 2024. Warnings cover flood areas, not individual addresses.

Recorded flood extents near the district (Environment Agency record):

Winter 2013/2014 (2013) — about 31.8 km from the centre

Records, not floods: no outline on the record is not evidence a place has not flooded.

🏠 Buying or renting in HP4? The full property flood-risk report covers any postcode here — the official likelihood band, every recorded flood nearby with distances, warning history year by year, how the local rivers behave, and an insurance outlook, print-ready for £19. See what's in the report →

Flood risk in nearby postcode districts

HP3 HP5 HP1 HP7 HP8 HP10 HP11 HP12

Band = the worst likelihood band of any property in that postcode (EA Risk of Flooding from Rivers & Sea, defence-adjusted, area-level). Check any postcode in detail — or get the full £19 property report — at the property flood-risk report. © Environment Agency copyright and/or database right 2025. All rights reserved. Some features of this map are based on digital spatial data from the Centre for Ecology & Hydrology, © NERC (CEH). © Crown Copyright and Database Rights 2025 OS AC0000807064. This product is produced in part from PAF® and Multiple Residence Data, the copyright in which is owned by Royal Mail Group Limited and/or Royal Mail Group plc. All rights reserved. Licence number AC0000807064.