SA20 0AA - Flood, Heat, Air & Subsidence Risk - Llanymddyfri

Carmarthenshire, Llanymddyfri

SA20 0AA in Llanymddyfri has a High flood risk. Heat risk is Lower, with a median (50th percentile) of 12 days above 25°C per year, averaged over the 2021-2040 period under the RCP8.5 high emissions scenario (Met Office UKCP18). Air quality is Low at PM2.5 4.3 μg/m³, within the WHO annual guideline of 5 μg/m³ (Defra UK-AIR). Ground conditions are Low risk, with River Terrace Sand/Gravel geology; shrink-swell risk is classed as improbable (BGS GeoSure).

• Flood: Plan with flood risk in mind for this area.
• Heat: Projected 12 days above 25°C per year, 2021-2040 average (Met Office UKCP18, 50th percentile under RCP8.5).
• Air quality: PM2.5 4.3 µg/m³ - within the WHO annual guideline of 5 µg/m³ (Defra UK-AIR).
• Ground: BGS data: River Terrace Sand/Gravel geology. Shrink-swell risk classed as improbable (British Geological Survey).

Flood risk at SA20 0AA is rated High, based on Natural Resources Wales flood mapping.

Air quality at SA20 0AA is rated Low, based on Defra UK-AIR annual mean PM2.5 data. Fine particulate matter (PM2.5) comes primarily from road traffic, industry, and domestic burning. Long-term exposure above the WHO guideline of 5 µg/m³ is linked to respiratory and cardiovascular health risks. Buyers and renters in higher air quality risk areas may wish to consider whether the property is near busy roads or industrial sources.

BGS GeoSure data classes the underlying soil at SA20 0AA as River Terrace Sand/Gravel, with shrink-swell hazard rated improbable (subsidence risk band: Low). Soil type and shrink-swell behaviour drive subsidence claims following dry summers; recent ABI data shows insurer payouts rose sharply after the 2022 and 2025 hot summers. A structural survey is the reliable way to assess ground risk for a specific property.

This LocalRisk report for SA20 0AA draws on four official UK open data sources: Natural Resources Wales flood mapping, Met Office UKCP18 climate projections, Defra UK-AIR PM2.5 monitoring, and British Geological Survey GeoSure subsidence mapping. Risk ratings are a screening tool, complementing - not replacing - the searches and surveys ordered as part of a property transaction. Data covers Carmarthenshire and is updated as new official datasets are published.

Carmarthenshire spans a large rural area from upland catchments to low-lying valleys and coast and experiences cool, wet winters and mild summers, shaped by Atlantic weather and varied topography.

Natural Resources Wales flood zone data places SA20 0AA in the high flood risk band. The band reflects the highest flood risk within the postcode; some properties within this postcode may face little or no direct flood risk. A formal flood risk search and review of buildings insurance availability is recommended before any property transaction in this area.