LOCATION

PO17 5BD - Flood, Heat, Air & Subsidence Risk - Wallington & Downend

Fareham, Wallington & Downend

Flood: Very lowHeat: MediumAir quality: MediumGround: Medium

PO17 5BD in Fareham has a Very low flood risk - EA NaFRA2 data records no properties in a flood risk zone in this postcode. Heat risk is Medium, with a median (50th percentile) of 28 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 Medium at PM2.5 6.3 μg/m³, above the WHO annual guideline of 5 μg/m³ (Defra UK-AIR). Ground conditions are Medium risk, with Chalk geology; shrink-swell risk is classed as possible (BGS GeoSure).

National comparison

  • Air pollution: cleaner than 56% of councils
  • Heat risk: hotter than 58% of councils
  • Subsidence risk: higher risk than 87% of postcodes
  • Green space access: less green access than 95% of English postcodes

Flood risk at PO17 5BD is rated Very Low, based on Environment Agency NaFRA2 modelling.

Heat risk at PO17 5BD is rated Medium, reflecting Met Office UKCP18 climate projections (50th percentile) for this area, averaged over the 2021-2040 period under the RCP8.5 high emissions scenario. These are probabilistic projections - the 50th percentile is the central estimate within RCP8.5; the full range of modelled outcomes is wide and lower emissions scenarios would produce lower figures. Higher summer temperatures increase cooling energy costs, affect comfort in poorly insulated or south-facing properties, and can accelerate shrinkage in clay soils beneath foundations. Properties built before 1980 without cavity wall insulation are typically most affected.

Air quality at PO17 5BD is rated Medium, 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 PO17 5BD as Chalk, with shrink-swell hazard rated possible (subsidence risk band: Medium). 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 PO17 5BD draws on four official UK open data sources: Environment Agency NaFRA2 flood modelling, 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 Fareham and is updated as new official datasets are published.

Fareham has a coastal and suburban setting along Portsmouth Harbour and experiences cool, wet winters and warm summers, influenced by maritime conditions and low-lying land.

Environment Agency flood zone data shows very low flood risk for PO17 5BD in Fareham. EA NaFRA2 data shows no properties at flood risk in this postcode. The band reflects the highest flood risk within the postcode; some properties within this postcode may face little or no direct flood risk. For a specific property, a conveyancing search will confirm the exact flood zone position.

Practical check: With 28 hot days projected (UKCP18 50th percentile, 2021-2040 average under RCP8.5), note which bedrooms face west (hottest in evening) and whether windows allow through-ventilation. With chalk geology here, look for signs of ground movement - diagonal cracks above windows, sticking doors, and gaps between walls and extensions. These are postcode-level indicators - conditions vary between individual properties.