Harrow Flood Risk
Harrow has a Low flood risk from rivers and the sea , with 1.3% of homes in a Medium or High band. The nearest gauge is 2.3 km away.
Harrow has 260,725 residents and 97,368 homes. Ranked 1711 of 7,114 in England for rivers and sea flood risk.
What Is The River Level Near Harrow Right Now?
Read from the Environment Agency flood-monitoring feed at 20 Sept, 14:34 UTC. The highest level on record here is 2.092 m , reached on 26 August 2015.
When Has Harrow Flooded Before?
The Environment Agency holds 10 recorded flood outlines covering Harrow, the most recent dated 26 June 2016.
Absence of a record is not evidence that a place has never flooded — the Environment Agency states that a lack of coverage does not mean an area has never flooded.
What Does Harrow's Flood Risk Classification Mean?
2.4% of postcodes in Harrow sit in Flood Zone 3, the planning band for land with a 1% or greater annual chance of river flooding or 0.5% or greater of sea flooding — and the map that draws it deliberately ignores flood defences.
The flood risk band for rivers and the sea is Low , with 1.3% of homes in a Medium or High band. Unlike the Flood Zone, the band counts the defences that are actually in place, which is why the two can describe the same street differently and both be right.
Which Postcode Districts Cover Harrow?
Each district below is one postcode district that falls inside Harrow. The band is the one shared by most of that district's postcodes, so it describes the district rather than a single street — enter a full postcode in the checker for one address. A district can cover more than one town, and the district pages linked from the checker are keyed to the town that holds most of its postcodes.
| Postcode district | Postcodes here | Rivers and sea band | Surface water addresses |
|---|---|---|---|
| HA3 | 926 | High | 5,974 |
| HA2 | 924 | High | 5,516 |
| HA1 | 847 | High | 3,335 |
| HA7 | 796 | High | 2,436 |
| HA5 | 781 | High | 2,605 |
| HA8 | 388 | High | 1,796 |
| UB5 | 18 | Medium | 72 |
| NW9 | 4 | High | 1 |
| WD23 | 3 | Low | 1 |
| HA4 | 2 | High | 9 |
| UB6 | 2 | Not mapped — no rivers-and-sea band covers this district | not published for this district |
"Not mapped" is not "no risk". It means no rivers-and-sea band covers that district in the source — surface water can still flood it, and both Camden and Islington flooded from surface water in July 2021 while carrying no mapped rivers-and-sea band.