Carmarthen Flood Risk
Carmarthen has a Low flood risk from rivers and the sea , with 1.1% of homes in a Medium or High band.
Carmarthen has 15,961 residents and 7,232 homes. Ranked 236 of 621 in Wales for rivers and sea flood risk.
When Has Carmarthen Flooded Before?
The Environment Agency holds 14 recorded flood outlines covering Carmarthen, the most recent dated 4 November 2025.
Absence of a record is not evidence that a place has never flooded — the Environment Agency states that a lack of coverage does not mean an area has never flooded.
What Does Carmarthen's Flood Risk Classification Mean?
8.5% of postcodes in Carmarthen sit in Flood Zone 3, the planning band for land with a 1% or greater annual chance of river flooding or 0.5% or greater of sea flooding — and the map that draws it deliberately ignores flood defences.
The flood risk band for rivers and the sea is Low , with 1.1% of homes in a Medium or High band. Unlike the Flood Zone, the band counts the defences that are actually in place, which is why the two can describe the same street differently and both be right.
Which Postcode Districts Cover Carmarthen?
Each district below is one postcode district that falls inside Carmarthen. The band is the one shared by most of that district's postcodes, so it describes the district rather than a single street — enter a full postcode in the checker for one address. A district can cover more than one town, and the district pages linked from the checker are keyed to the town that holds most of its postcodes.
| Postcode district | Postcodes here | Rivers and sea band | Surface water addresses |
|---|---|---|---|
| SA31 | 473 | Low | not published for this district |