eafm integration offers integration with the UK Environment Agency Flood Monitoring API to provide sensors for nearby water levels. Combined with Home Assistant notifications, you could give yourself a warning if a nearby river was likely to flood your local cycle path or the only road out of your village.
The UK Environment Agency Flood Monitoring only provides data for England - Northern Ireland, Scotland and Wales have their own flood agencies.
Home Assistant offers the flood monitoring integration through Configuration -> Integrations -> Environment Agency Flood Gauges.
You will be prompted to select a monitoring station. You can find the name of nearby monitoring stations on the Flood information service website.
Sensors for that monitoring station should then appear in your Home Assistant instance.