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Conna CastlePhoto: Glenrua66 who is Lorna Macdonald, the photographer · CC BY 3.0
–Not graded
Flood & hazards in Conna · EPA, GSI and OPW data

Conna has low radon and steady ground, but its flood exposure isn’t measured

Conna has no Hazard risk Grade: Irish places under 1,000 residents aren’t graded. The figures below are still its own.

2.1%of homes over the radon level
In brief

What stands out about Conna’s hazards

From the EPA’s radon map, Geological Survey Ireland’s landslide map, the OPW’s flood relief schemes and our estimate of low-lying homes, below.

Flooding not measuredNo detailed ground heights cover Conna, so how many of its homes stand low by big water isn’t measured.Some radonAbout 2.1% of homes are estimated above the radon reference level, a lower share than in 70% of Irish towns; 0% of homes are in a High Radon Area.Steady groundNo home stands on ground rated high or moderately high for landslides; 36% of Irish towns have some homes on it.
By hazard

What Conna faces

Each hazard against its own yardstick; meters run from low to high on that yardstick.

Low-lying homes

Not measured
No detailed heights here
Check the official flood maps

Radon

2.1%of homes estimated over the reference level
less radon than in 70% of Irish towns
0% of homes in a High Radon Area

Landslides

0%of homes on high or moderately high ground
No home on landslide-prone ground
Rated from the ground and its slope

Ground heights

0%of homes on detailed ground heights
Too few to count flood (80% needed)
Of 95 homes counted
Not on this page: the OPW’s official flood maps and past floods (their licence doesn’t allow reuse here: see floodinfo.ie), groundwater and surface-water flooding, coastal erosion and industrial sites.
Hazard risk Grade

Conna has no Hazard risk Grade

Radon (2.1%)Better than 70% of Irish towns
Landslide ground (0%)None on landslide-prone ground
Low-lying homesNot counted: not measured here

Each figure is placed among Irish towns as the grade would place it, without a letter.

Less sure: The low-lying figure is our estimate from ground heights and the river map, not an official flood map. It can show a town is low-lying; it can’t show a town is safe. No LiDAR here: the heights come from a 30 m satellite model, which reads roofs and trees as ground, so this town’s figure isn’t counted. A small place (95 homes): a few houses move the figure a lot.

Low-lying homes

How many of Conna’s homes stand low isn’t measured

Low-lying homes, a TownRatings estimate from OPW and Geological Survey Ireland LiDAR ground heights and the EPA’s river map: not an official flood map.

Flooding isn’t measured in Conna: no LiDAR survey covers its homes, and the measure needs 80% of them, so flood isn’t counted for or against it. That doesn’t mean it doesn’t flood.

A rougher estimate, mostly from a 30 m satellite model, puts about 9.5% of homes low beside the River Bride. That model reads roofs and trees as ground, so it misses low homes more often than it invents them.

Official flood maps and past floods: floodinfo.ie

River levels

The River Bride at Mogeely peaked at 2.77 m in December 2015

Each winter’s highest level (October to September) at the OPW’s Mogeely gauge, 2.2 km from Conna on the same river, since 1972, in metres above the gauge’s zero. Nine days in ten it runs between 0.17 m and 0.98 m.

Each winter’s highest level, metres
Winter 1972–73: highest 2.06 m · 22 days above the normal rangeWinter 1973–74: highest 2.27 m · 54 days above the normal rangeWinter 1974–75: highest 1.84 m · 12 days above the normal rangeWinter 1975–76: highest 2.21 m · 12 days above the normal rangeWinter 1976–77: highest 1.92 m · 45 days above the normal rangeWinter 1977–78: highest 2.28 m · 40 days above the normal rangeWinter 1978–79: highest 2.20 m · 33 days above the normal rangeWinter 1979–80: highest 2.10 m · 43 days above the normal rangeWinter 1980–81: highest 1.97 m · 48 days above the normal rangeWinter 1981–82: highest 2.25 m · 21 days above the normal rangeWinter 1982–83: highest 2.06 m · 20 days above the normal rangeWinter 1983–84: highest 2.08 m · 25 days above the normal rangeWinter 1984–85: highest 2.20 m · 25 days above the normal rangeWinter 1985–86: highest 2.46 m · 22 days above the normal rangeWinter 1986–87: highest 2.31 m · 53 days above the normal rangeWinter 1987–88: highest 2.22 m · 32 days above the normal rangeWinter 1988–89: highest 2.65 m on 11 October 1988 · 20 days above the normal rangeWinter 1989–90: highest 2.05 m · 29 days above the normal rangeWinter 1990–91: highest 1.44 m · 18 days above the normal rangeWinter 1991–92: highest 2.09 m · 10 days above the normal rangeWinter 1992–93: highest 1.97 m · 38 days above the normal rangeWinter 1993–94: highest 2.29 m · 47 days above the normal rangeWinter 1994–95: highest 2.58 m on 10 March 1995 · 46 days above the normal rangeWinter 1995–96: highest 2.33 m · 38 days above the normal rangeWinter 1996–97: highest 1.60 m · 20 days above the normal rangeWinter 1997–98: highest 2.39 m · 35 days above the normal rangeWinter 1998–99: highest 2.35 m · 29 days above the normal rangeWinter 1999–00: highest 1.99 m · 14 days above the normal rangeWinter 2000–01: highest 2.35 m · 33 days above the normal rangeWinter 2001–02: highest 2.03 m · 33 days above the normal rangeWinter 2002–03: highest 2.36 m · 32 days above the normal rangeWinter 2003–04: highest 1.78 m · 14 days above the normal rangeWinter 2004–05: highest 2.32 m · 21 days above the normal rangeWinter 2005–06: highest 2.19 m · 32 days above the normal rangeWinter 2006–07: highest 2.36 m · 40 days above the normal rangeWinter 2007–08: highest 2.13 m · 22 days above the normal rangeWinter 2008–09: highest 2.58 m on 30 January 2009 · 38 days above the normal rangeWinter 2010–11: highest 2.16 m · 12 days above the normal rangeWinter 2011–12: highest 2.58 m on 28 June 2012 · 41 days above the normal rangeWinter 2012–13: highest 2.22 m · 29 days above the normal rangeWinter 2013–14: highest 2.21 m · 63 days above the normal rangeWinter 2014–15: highest 2.11 m · 19 days above the normal rangeWinter 2015–16: highest 2.77 m on 30 December 2015 · 68 days above the normal rangeWinter 2016–17: highest 2.02 m · 15 days above the normal rangeWinter 2017–18: highest 2.43 m · 34 days above the normal rangeWinter 2018–19: highest 2.49 m · 38 days above the normal rangeWinter 2019–20: highest 2.16 m · 37 days above the normal rangeWinter 2020–21: highest 2.47 m · 53 days above the normal rangeWinter 2021–22: highest 2.24 m · 27 days above the normal rangeWinter 2022–23: highest 2.25 m · 73 days above the normal rangeWinter 2023–24: highest 2.76 m on 18 October 2023 · 81 days above the normal rangeWinter 2024–25: highest 2.33 m · 40 days above the normal rangeWinter 2025–26: highest 2.42 m · 71 days above the normal range’15–16’23–24Record 2.77 m, 2015Top of normal range
1972–732025–26
The highest days on record
  • 30 December 20152.77 m
  • 18 October 20232.76 m
  • 19 November 20092.66 m
  • 11 October 19882.65 m
  • 28 June 20122.58 m
  • 10 March 19952.58 m

Since 1972 the River Bride has run above its usual top on 1,817 days, most of them in the winters of 2023–24 and 2022–23.

Measured by its highest day, last winter (2025–26) was the 11th-highest of the 53 on record here.

Source: OPW Hydro-Data (waterlevel.ie/hydro-data), Mogeely gauge (station 18001): daily maximum and mean levels, inspected and provisional data. The usual range is the 5th to 95th percentile of daily means, worked out by TownRatings. Live levels are on waterlevel.ie.

Warnings

Weather and flood warnings for Conna

Where to see the warnings in force, and what this page can’t count.

Met Éireann issues yellow, orange and red warnings for rain, wind and coastal flooding county by county; Conna is covered by County Cork’s.

WarningWhat Met Éireann means by it
YellowWeather that isn’t unusual but can be dangerous in places: be aware.
OrangeInfrequent, dangerous weather that can put people and property at risk: be prepared.
RedRare, extremely dangerous weather: take action to protect yourself and your property.

Met Éireann doesn’t publish an open archive of past warnings, so how often warnings have covered Conna can’t be counted here.

Met Éireann warnings · OPW river levels (waterlevel.ie)

Flood scheme

No OPW flood relief scheme protects Conna

The Office of Public Works’ completed flood relief schemes and the areas each one benefits (OPW open data, CC BY 4.0).

Schemes
0
protect homes in Conna
Protected places in the county
3
Mallow, Fermoy, Dunmanway
Nearest protected place
13 km
Fermoy, as the crow flies
Low-lying homes
Not measured
the share a scheme would be built for

None of the OPW’s completed flood relief schemes has a benefiting area that takes in Conna’s homes. The OPW builds schemes where the risk to homes is greatest, so most towns have none.

In County Cork, OPW schemes protect parts of 3 other places, including Mallow, Fermoy, Dunmanway.

The protected places nearest here
TownSchemeDesigned forHomes behind itAway
Fermoy CorkFermoy South Flood Relief Scheme1 in 1006.3%13 km
Mallow CorkMallow South & West Flood Relief Scheme1 in 1002.6%37 km
Clonmel TipperaryClonmel (North & East) Flood Relief Scheme1 in 1007.4%41 km
Carrick-on-Suir TipperaryCarrick-on-Suir Flood Relief Scheme1 in 504.3%56 km
Kilbarry WaterfordWaterford (Phase 2,3 & 4) Flood Relief Scheme1 in 1000.3%68 km
Annacotty LimerickMulkear River (Ballymackeogh) Flood Relief Scheme1 in 101.1%70 km

Official flood maps and past floods: floodinfo.ie

Landslides

No home in Conna stands on landslide-prone ground

Geological Survey Ireland’s landslide susceptibility map (1:50,000), read at every home.

Homes on ground rated high or moderately high

ConnaCounty Cork’s medianmedian of Irish towns
High or moderately high0%
0%5%

Conna is among the 64% of Irish towns with no home on such ground.

GSI rates ground from low to high by its slope, soil and rock. Most Irish landslides are on steep upland slopes and peat after heavy rain; a town on flat ground has almost none.

High means the ground could slide under the right conditions, such as days of heavy rain on a steep, wet slope; it isn’t a forecast that it will.

GSI landslide susceptibility, high and moderately high classes, share of the town’s homes on mapped ground (CC BY 4.0).

Radon

An estimated 2.1% of Conna’s homes are above the radon reference level

The EPA’s radon map: for each 10 km square, the estimated share of homes above the national reference level of 200 Bq/m³.

1.2% of homes estimated above the reference level · 1–5% of homes13% of homes estimated above the reference level · 10–20% (High Radon Area)8.8% of homes estimated above the reference level · 5–10% of homes8.1% of homes estimated above the reference level · 5–10% of homes9.4% of homes estimated above the reference level · 5–10% of homes0.3% of homes estimated above the reference level · Under 1% of homes14% of homes estimated above the reference level · 10–20% (High Radon Area)5.6% of homes estimated above the reference level · 5–10% of homes2.1% of homes estimated above the reference level · 1–5% of homes0.2% of homes estimated above the reference level · Under 1% of homes3.9% of homes estimated above the reference level · 1–5% of homes19% of homes estimated above the reference level · 10–20% (High Radon Area)under 0.1% of homes estimated above the reference level · Under 1% of homes© OpenStreetMap contributors · EPA
Under 1% of homes1–5% of homes5–10% of homes10–20% (High Radon Area)
Share of Irish towns in each band
Under 1% of homes17%
1–5% of homes · Conna38%
5–10% of homes26%
10–20% (High Radon Area)11%
Over 20% (High Radon Area)9%

A square where 10% or more of homes are estimated above the reference level is a High Radon Area; 0% of Conna’s homes are in one. The map is an estimate by area: two neighbouring houses can differ a lot.

0%
of homes in a High Radon Area
5.7%
County Cork’s median
4%
median of Irish towns

A test is the only way to know a home’s level: two detectors, left for three months in a living room and a bedroom.

EPA radon map of Ireland (10 km grid), averaged over the town’s homes (CC BY 4.0).

Industrial sites

No EPA-licensed site within 5 km of Conna: the nearest is 11 km away

Factories, farms, power plants and waste sites that hold an EPA licence for their emissions, in Conna and around its centre.

0
licensed sites inside Conna
0
licensed sites within 5 km of the centre
11 km
to the nearest: Veolia Environmental Services Technical Solutions Ltd, Corrin, Fermoy, Cork
The nearest licensed site
SiteLicence and activityAway
Veolia Environmental Services Technical Solutions Ltd, Corrin, Fermoy, CorkIndustrial Emissions licence · waste11 km

An EPA licence sets what a site may release to air, water and land; it doesn’t mark the site as an accident hazard.

Sites holding dangerous substances in bulk come under the COMAH (Seveso) rules, but the HSA’s list of them has no open licence, so upper- and lower-tier sites aren’t counted here.

Source: EPA registers of Industrial Emissions, IPC and waste licences, sites licensed on 31 October 2026; distances in a straight line from the town’s centre.

Neighbours

Hazards in the places around Conna

Low-lying homes, radon and landslide ground, town by town.

TallowRathcormacFermoyKilworthLismoreWatergrasshillTallowRathcormacFermoyKilworthLismoreWatergrasshillConna
TownLow-lyingRadonLandslides
Conna–2.1%0%
Tallow
1,022 · 7.3 km		5.2%1.8%0.5%
Rathcormac
1,957 · 12 km		0%9.4%0%
Fermoy
6,720 · 13 km		5.9%9.7%0.1%
Kilworth
1,179 · 13 km		0%0.3%0%
Lismore
1,347 · 13 km		0%under 0.1%0.9%
Watergrasshill
1,840 · 19 km		–1.2%0%

Of the places around Conna, Fermoy has the most homes standing low by big water (5.9%), 13 km away.

A dash under Low-lying: not measured there (too few homes with detailed ground heights), not none.

Be ready

Get ready for what Conna faces

What to do, and what to ask before you move.

When the river rises
  • Never walk or drive through floodwater: 30 cm of moving water can float a car.
  • Move valuables, papers and medicines upstairs.
  • Turn off gas, electricity and water if you’re told to.
Met Éireann warnings · floodinfo.ie
Radon
  • Test over three months, in a living room and a bedroom.
  • Above 200 Bq/m³, a small sump and fan usually fixes it.
  • The EPA sells radon test kits at radon.ie and lists registered contractors who fix high readings.
radon.ie
When a storm is forecast
  • Bring in or tie down bins, trampolines and anything the wind can lift.
  • Keep away from coastal paths and piers while an orange or red warning is in force.
  • Charge phones and keep a torch: fallen lines are the commonest storm damage.
  • After the storm, report a fallen line to ESB Networks and keep well clear of it.
ESB Networks PowerCheck
Before you buy or rent in Conna
  • Ask whether the home has ever flooded, and get a buildings insurance quote before you commit: flood cover isn’t always offered.
  • Ask the seller or landlord for a radon test result, or test in your first months there.
  • Check the address on floodinfo.ie: the OPW’s flood maps and its record of past floods.
How to read these numbers

What this data can and can’t tell you

  • An estimate, not a flood map. Low-lying homes is a TownRatings modelling step: each home’s ground height from LiDAR, against the level of the nearest big river (Strahler order 5 or more), lake or estuary within 1 km, or the sea within 2 km. A home within 5 m of the water’s level, or below 4 m near the sea, counts.
  • Flood counts only one way. A high share of low-lying homes lowers the Hazard risk Grade; a low share never raises it, because defences, small streams, culverts, groundwater and flash floods don’t show in ground heights. Below the national median a town scores as the median.
  • Defences aren’t counted. Flood defences aren’t taken off: the OPW scheme that protects the most homes is shown instead, with its design standard.
  • Measured where the heights are detailed. A town is measured, and counted, only where 80% of its homes stand on LiDAR heights. Elsewhere the page says flooding isn’t measured, never that the town is dry.
  • Radon is an estimate by area. The EPA’s radon map gives the estimated share of homes above 200 Bq/m³ for each 10 km square, averaged here over the town’s homes. It says where to test, not what one house holds.
  • The sea is measured by height. Homes count as low by the sea when their ground is under 4 m and within 2 km of coastal or estuary water; waves, surges and erosion aren’t modelled.
  • Landslide ground is a map of where slides could start. GSI’s susceptibility map rates the ground itself; it doesn’t record past slides or say when one will happen.
  • Bathing water is rated season by season. The EPA classes each identified bathing water from four seasons of samples; a rating says how clean the water has been, not how safe it is to swim.
  • One town, many streets. Risk is street by street. Check a specific address on floodinfo.ie before you buy or rent.

Check any address against the OPW’s official flood maps on floodinfo.ie

Questions about flooding and hazards in Conna

Does Conna flood?

For a single address, the OPW’s official flood maps and past floods are on floodinfo.ie.

Is radon a problem in Conna?

The EPA’s map estimates that about 2.1% of homes around Conna are above the radon reference level of 200 Bq/m³: a lower share than in 70% of Irish towns. 0% of its homes are in a High Radon Area. The only way to know a house is a three-month test.

Is Conna at risk of landslides?

No home in Conna stands on ground rated high or moderately high for landslides.

How does Conna compare with the places around it?

Radon estimates around Conna run from under 0.1% in Lismore to 9.7% in Fermoy; Conna’s own is 2.1%. Among the places measured in detail, Fermoy has the largest share of homes standing low (5.9%).

Flood: TownRatings’ estimate from ground heights, not an official flood map. Contains Irish Public Sector Data (Geological Survey Ireland, the Office of Public Works and the EPA) licensed under CC BY 4.0; Copernicus DEM © DLR e.V. and © Airbus, provided under COPERNICUS by the EU and ESA; © OpenStreetMap contributors. Radon and bathing water: EPA (CC BY 4.0). Landslide susceptibility: Geological Survey Ireland (CC BY 4.0).

Sources: low-lying homes: TownRatings’ estimate from GSI and OPW LiDAR, Copernicus GLO-30 and the EPA river network · radon: EPA radon map · landslides: GSI landslide susceptibility · river levels: OPW Hydro-Data (waterlevel.ie/hydro-data) · industrial sites: EPA licence registers. Under Creative Commons Attribution 4.0 (CC BY 4.0).

Contains Central Statistics Office (CSO) data, Census 2022, and Tailte Éireann boundaries (CSO Urban Areas, Small Areas, local electoral areas, constituencies), under Creative Commons Attribution 4.0 (CC BY 4.0).