Properties at risk of flooding in Wales
See what variables and values are shown in your table
| Variable | Visibility | Selected values | Action |
|---|---|---|---|
| Data description | Shown in table | Properties at risk | Value cannot be changed |
| Flooding Type | Shown in table | All 3 values | Change values |
| Risk | Shown in table | All 4 values | Change values |
| Property Type | Shown in table | All 3 values | Change values |
| Defence Type | Shown in table | All 2 values | Change values |
| Area | Shown in table | All 26 values | Change values |
| Year | Shown in table | All 3 values | Change values |
Table
Standard shorthand is used in this table: [f] = forecast, [t] = total.
| Data values | Data description | Flooding Type | Risk | Property Type | Defence Type | Area | Year |
|---|---|---|---|---|---|---|---|
| 104,952 [t] | Properties at risk | Rivers | Total | Total | Defended | Wales | 2025 |
| 103,801 [t] | Properties at risk | Rivers | Total | Total | Defended | Wales | 2024 |
| 128,414 [f] [t] | Properties at risk | Rivers | Total | Total | Defended | Wales | 2120 |
| 25,001 [t] | Properties at risk | Rivers | Total | Total | Defended | North Wales | 2025 |
| 24,619 [t] | Properties at risk | Rivers | Total | Total | Defended | North Wales | 2024 |
| 31,174 [f] [t] | Properties at risk | Rivers | Total | Total | Defended | North Wales | 2120 |
| 30,548 [t] | Properties at risk | Rivers | Total | Total | Defended | Mid & South West Wales | 2025 |
| 30,422 [t] | Properties at risk | Rivers | Total | Total | Defended | Mid & South West Wales | 2024 |
| 38,625 [f] [t] | Properties at risk | Rivers | Total | Total | Defended | Mid & South West Wales | 2120 |
| 49,403 [t] | Properties at risk | Rivers | Total | Total | Defended | South East Wales | 2025 |
| 48,760 [t] | Properties at risk | Rivers | Total | Total | Defended | South East Wales | 2024 |
| 58,615 [f] [t] | Properties at risk | Rivers | Total | Total | Defended | South East Wales | 2120 |
| 306 | Properties at risk | Rivers | Total | Total | Defended | Isle of Anglesey | 2025 |
| 306 | Properties at risk | Rivers | Total | Total | Defended | Isle of Anglesey | 2024 |
| 394 [f] | Properties at risk | Rivers | Total | Total | Defended | Isle of Anglesey | 2120 |
| 3,639 | Properties at risk | Rivers | Total | Total | Defended | Gwynedd | 2025 |
| 3,638 | Properties at risk | Rivers | Total | Total | Defended | Gwynedd | 2024 |
| 4,716 [f] | Properties at risk | Rivers | Total | Total | Defended | Gwynedd | 2120 |
| 9,953 | Properties at risk | Rivers | Total | Total | Defended | Conwy | 2025 |
| 9,824 | Properties at risk | Rivers | Total | Total | Defended | Conwy | 2024 |
| 12,078 [f] | Properties at risk | Rivers | Total | Total | Defended | Conwy | 2120 |
| 4,274 | Properties at risk | Rivers | Total | Total | Defended | Denbighshire | 2025 |
| 4,162 | Properties at risk | Rivers | Total | Total | Defended | Denbighshire | 2024 |
| 5,247 [f] | Properties at risk | Rivers | Total | Total | Defended | Denbighshire | 2120 |
| 5,202 | Properties at risk | Rivers | Total | Total | Defended | Flintshire | 2025 |
Next update expected:This dataset is not expected to be updated, but is expected to be replaced in the future
Updates
- 2nd October 2025
- Dataset first published.
Main information
- Designation
- No designation
- Data provider
- Natural Resources Wales
- Data source
- National Flood Risk Assessment data
Overview
- Summary of dataset and variables
The Flood Risk Assessment Wales (FRAW) modelling, together with the latest National Receptor Database 2025 (NRD 2025) are used to determine the number of properties (residential and non-residential) at risk of flooding from Rivers, the Sea and Surface Water and Small Watercourses in Wales. The information is for Present Day risk and Climate Change risk (2120) and includes both the presence and removal of flood defences within the modelling (defended and undefended scenarios).
- Data collection or calculation
The chance of flooding is set out in three risk categories:
High Risk; Greater than or equal to 1 in 30 (3.3%) chance in any given year Medium Risk; Less than 1 in 30 (3.3%) but greater than or equal to 1 in 100 (1%) chance in any given year for rivers and surface water flooding and less than 1 in 30 (3.3 per cent) but greater than or equal to 1 in 200 (0.5 per cent) for the sea. Low Risk; Less than 1 in 100 (1%) for rivers and surface water flooding and 1 in 200 (0.5 per cent) for the sea but greater than or equal to 1 in 1,000 (0.1%) chance in any given year.
FRAW typically includes flooding from rivers with a catchment size greater than 3 square kilometres, and flooding from the sea (both along the open coast and tidal estuaries). Smaller watercourses with a catchment size smaller than 3 square kilometres are represented in the FRAW Surface Water data and maps.
The assessment takes into account the location and standard of protection afforded by flood defences and adjusts the risk categorisation accordingly from an initial, ‘undefended’ scenario.
Climate change uplift values are based on the guidance available at the time of the original FRAW project which was completed in 2019. The uplift values are very similar or identical to current Welsh Government guidance, using a “Central Estimate”. Typical values for Sea level rise are approximately 1.1m across Wales, a 20% to 30% increase in River flows based on River Basin Catchments and a 20% increase to rainfall for the Surface Water and Small Watercourse mapping.
For the Climate Change Defended scenario, an assumption has been made that the existing standard of protection of the flood defences keeps pace with climate change.
- Statistical quality
FRAW typically includes flooding from rivers with a catchment size greater than 3 square kilometres, and flooding from the sea (both along the open coast and tidal estuaries). Smaller watercourses with a catchment size smaller than 3 square kilometres are represented in the FRAW Surface Water data and maps.
The assessment takes into account the location and standard of protection afforded by flood defences and adjusts the risk categorisation accordingly from an initial, ‘undefended’ scenario.
Some properties in Wales may be affected by more than one source of flooding, therefore when counting properties at risk, you need to be careful the same property isn’t counted more than once. For example, if a property is affected by all three sources of flooding, when reporting by flood sources it will be counted as one property for rivers, one for the sea and one for surface water & small watercourse. However, if you are counting the total number of properties in Wales at flood risk, using the sum of all three sources, the same property could be counted 3 times. The property counts provided are a snapshot in time based on datasets from that year. They are subject to change year on year, as data and methodology improves over time. This may cause counts to increase or decrease between individual releases. When we count buildings or properties, this may include multiple buildings at the same address.
In 2024 Natural Resource Wales produced a projection for properties at risk of flooding for 2120 for the first time, which has been updated this year. The current 2120 projection is based on the 2025 figures. Both the 2024 and 2025 figures provide property counts that represent a defended scenario in 2120 (i.e. in approximately 100years time). These estimates are based on the same underlying assumption that the existing standard of protection of flood defences will be maintained in the future but have been calculated in two slightly different ways:
- For the 2024 property counts, the future (2120) standard of protection of flood defences was set at 80% of the current standard. This meant that there was a reduction in the standard of protection meaning that some properties moved into higher risk bands.
- For the 2025 property counts, the calculation has been performed differently. There has been no reduction in the standard of protection and the current level is maintained in the future (i.e. a flood defence providing a 100year standard of protection today provides the same 100year standard of protection in 2120).
Differences between the 2024 and 2025 property counts show how susceptible the figures are to change with only a slight alteration to approach underlying the uncertainty when making future predictions.
The assumption that flood defences will be maintained to the same level of protection is only one possible outcome. The risk assigned to properties in defended areas could change greatly in the future depending on the levels of investment and maintenance, further information can be found at Natural Resources Wales / Long-term Investment Requirements for Flood Defences in Wales.
Published by
- Organisation
- Welsh Government
- Contact email
- stats.environment@gov.wales