HA7: 36 m clear of the highest tide in the London Bridge ledgers

The lowest postcode in HA7, HA7 1HG, stands 36 m above the highest tide in the London Bridge ledgers (5.41 m, 1 February 1953). The highest, HA7 3FR, stands 147 m above it.
- Ground at eight in ten of its postcodes: between 54 m and 116 m, measured from Ordnance Datum; the middle one stands at 75 m.
- None lies in the Environment Agency's Flood Zone 3 from the sea.
- Mostly in Harrow; partly in Brent.