Does SY21 flood?

Yes — parts of the SY21 district carry real flood risk: 5 of its 6 at-risk postcodes reach the Environment Agency's High likelihood band. The SY21 postcode district covers Chirbury & Worthen, Rhiwcynon, Trelystan and Trewern, Welshpool Castle, close to Crewgreen, Alberbury, On Prentre Brook approx 400m from confluence with River Severn., and surrounding villages in parts of Shropshire and Powys.

6 postcodes in the SY21 district appear in the Environment Agency's rivers-and-sea flood-risk dataset — worst bands: 5 high, 1 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 SY21 postcodes are at risk?

SY21 8DG up to High SY21 8JS up to High SY21 8JT up to High SY21 8JX up to High SY21 8JY up to High SY21 8JL up to Low

Rivers and flooding history near SY21

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

Crew Green on the River Severn — 13.5 km away, highest on record 6.58m
Farley Bridge on the Rea Brook — 14.2 km away, highest on record 2.51m
Hayes Basin on the Field Drain — 14.9 km away, highest on record 4.23m
Cae Howel on the New Cut — 15.4 km away, highest on record 6.27m

🏠 Buying or renting in SY21? 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

SY22 SY15 SY14 SY13 SY12 SY11 SY10 SY9

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.