Is Castleknock in a flood zone?

Parts of Castleknock are. The OPW has mapped river flood extents within about 1.5 km of the town centre. A zone covers streets, not the whole town, so the answer for one house depends on where it stands. The report checks the exact Eircode against the 1 in 10, 1 in 100 and 1 in 1000 year extents.

Will a house in Castleknock be hard to insure against flooding?

Insurers price by postcode and by the OPW record. With 6 recorded events within 2 km, expect questions on the proposal form and possibly a flood exclusion on some streets. Ask the seller for their current policy schedule: if flood is excluded, you will inherit that problem.

What does the paid report add for a house in Castleknock, Dublin?

It puts the Eircode point against every OPW flood extent, lists recorded floods within 500 m with dates and OPW notes, checks GSI groundwater flood maps and coastal erosion, and ranks the result against the other thirty-seven checks (radon, BER, planning, knotweed, title, sewer and more) for that one address.

Flood risk · Castleknock, Dublin

Flooding in Castleknock: 6 recorded floods, OPW flood zones

The OPW register holds 6 recorded floods within 2 km of the centre of Castleknock, and the OPW has mapped river flood extents nearby. What that means for a house here, and how to check the exact address.

Figures compiled from the public records listed at the foot of this page. Data snapshot: 2 October 2026. Updated when the records change.

Check one house in Castleknock

6 recorded floods within 2 km of Castleknock, OPW flood zones on the map.

One specific house in Castleknock: flood zone for that Eircode, recorded floods within 500 m, radon, planning applications within 300 m, BER, sale history. Thirty-eight checks in all, each linked to the public record.

€19.99, free snapshot first. No account.

Or read the sample report first: a real house, 16 pages.

recorded flood events within 2 km of the town centre (OPW)

Yes

river flood extent mapped nearby (1 in 100 year, OPW CFRAM)

coastal flood extent mapped nearby (1 in 200 year)

What the OPW record says about Castleknock

The Office of Public Works keeps a register of past floods. Within 2 km of the centre of Castleknock it holds 6 events, the latest in 2004. By source: river (4), runoff (2). A recorded event does not mean every street went under. It means an insurer’s model knows the town.

Most recent on file:

October 2004: Liffey Sommerton Rd Luttrellstown Golf C Oct 2004 (runoff).
November 2002: Liffey R109 at the Strawberry Beds Nov 2002 (river).
November 2002: M50 at the N3 Interchange Nov 2002 (runoff). Remedial measures to Road drainage have been undertaken since flooding occurred.
June 1993: Liffey Strawberry Beds June 1993 (river).
undated: Tolka Herbert Road Blanchardstown Undated (river).

Separately from past events, the OPW flood maps (CFRAM) draw modelled extents for river flooding near Castleknock. A house inside the 1 in 100 year river extent, or the 1 in 200 year coastal extent, will usually need a flood-specific conversation with the insurer before you can draw down a mortgage.

What to do before bidding on a house here

Look the exact address up on the OPW map, not the town. Two houses on the same road can sit on opposite sides of an extent line. Ask the seller in writing whether the house or garden has ever flooded and whether a flood claim was made. Ask for the current insurance schedule. If the house is inside an extent, get a quote before going sale agreed: some insurers decline outright, and the bank will not lend without cover.

The report on this site checks flood for one Eircode in about a minute. The paid report adds the distance to each recorded event, which extents the point falls in, and the GSI groundwater map, all with links to the source so a solicitor can rely on them.

Also for Castleknock

Radon in Castleknock · Planning applications in Castleknock · BER ratings in Castleknock · Flood risk across Dublin

Nearby: Blanchardstown, Palmerstown, Clonsilla, Ballyfermot, Hansfield, Clonee.

Other checks for Castleknock

Radon in Castleknocklow radon area
Japanese knotweed in Dublin364 records
BER ratings in Castleknocktypical B3
Planning applications in Castleknock535 applications
Planning permission in FingalFingal County Council
Planning permission in Dublin50,621 applications

GuideIs my house in a flood zone? What the OPW maps say and what insurers do with them

Questions people ask

Is Castleknock in a flood zone?: Parts of Castleknock are. The OPW has mapped river flood extents within about 1.5 km of the town centre. A zone covers streets, not the whole town, so the answer for one house depends on where it stands. The report checks the exact Eircode against the 1 in 10, 1 in 100 and 1 in 1000 year extents.
Will a house in Castleknock be hard to insure against flooding?: Insurers price by postcode and by the OPW record. With 6 recorded events within 2 km, expect questions on the proposal form and possibly a flood exclusion on some streets. Ask the seller for their current policy schedule: if flood is excluded, you will inherit that problem.
What does the paid report add for a house in Castleknock, Dublin?: It puts the Eircode point against every OPW flood extent, lists recorded floods within 500 m with dates and OPW notes, checks GSI groundwater flood maps and coastal erosion, and ranks the result against the other thirty-seven checks (radon, BER, planning, knotweed, title, sewer and more) for that one address.

Sources

Area figures, compiled from public records. They describe the town or county, not any one house. The paid report checks the exact Eircode.