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Birr - Main Street looking towards O'Connell StreetPhoto: Colin Park · CC BY-SA 2.0
B+Hazard risk Grade
Flood & hazards in Birr · EPA, GSI and OPW data

Low radon, steady ground, few homes by big water: Birr is light on natural hazards

With 1.8% of its homes standing low beside the River Little Brosna, Birr grades B+ for hazard risk, #98 of 321 Irish towns; flood counts only against a town, and here it does.

2.5%of homes over the radon level
In brief

What stands out about Birr’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.

Few homes by big waterUnder 2% of homes stand low by a big river, lake or the sea. Small streams, drains and groundwater aren’t in that measure.Some radonAbout 2.5% of homes are estimated above the radon reference level, a lower share than in 68% 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 Birr faces

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

Low-lying homes

1.8%of homes low by a big river, lake or the sea
a higher share than in 58% of Irish towns
About 39 homes

Radon

2.5%of homes estimated over the reference level
less radon than in 68% 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

100%of homes on detailed ground heights
Enough to measure flood (80% needed)
Of 2,141 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

Birr grades B+ for hazard risk

Radon, landslide ground and low-lying homes, each against Irish towns, then averaged.

Radon (2.5%)Better than 62% of Irish towns
Landslide ground (0%)Better than 57% of Irish towns
Low-lying homes (1.8%)Better than 44% of Irish towns · counted against it

Each figure is placed among Irish towns of 1,000 or more people; the grade averages the three, so a better place on each is a better grade.

Flood counts only against a town, and Birr’s share of low-lying homes is high enough to lower its grade.

Its place: #98 of 321 Irish towns.

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.

Low-lying homes

Few of Birr’s homes stand low by a big river, lake or the sea

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. Smaller streams, drains and groundwater aren’t in this measure, so a low figure doesn’t mean a town never floods.

By a river, lake or estuary1.8%of homes within 5 m of the water’s level
Near the sea0%of homes below 4 m, within 2 km of the sea
Measured in detail100%of homes on detailed ground heights
Where Birr sits among 231 Irish towns
43%None
6%Under 0.5%
4%0.5–1%
7%1–2%Birr
8%2–5%
6%5–10%
8%10–20%
18%20% +

Share of each town’s homes standing low by big water, for the towns measured in detail. 43% have none; Birr has more than 58% of them.

Towns its size: 22nd of 40, from the fewest low-lying homes
#TownPeopleLow-lying
1Portobello Dublin5,7320%
2Blessington Wicklow5,6110%
3Roscrea Tipperary5,5420%
…
20Garryowen Limerick5,4281%
21Courtown Wexford4,3651.7%
22Birr Offaly4,7261.8%
23Macroom Cork4,0961.9%
24Dangan Galway4,6213.7%
…
39Woodquay and Nuns Island Galway4,94857%
40Cork City Centre Cork3,701100%

The 40 Irish towns nearest its size that are measured in detail.

2,141
homes counted
39
homes standing low by big water
0.8%
County Offaly’s median
0.7%
median of Irish towns

Low-lying homes across County Offaly’s towns · 4 towns measured in detail

Birr1.8%
Clara1.6%
Tullamore0%
Edenderry0%

Birr ranks 1st of County Offaly’s 4 towns measured in detail, counting from the most low-lying homes.

Homes: OpenStreetMap buildings of 30 m² or more, not tagged as non-residential, in the town’s Census 2022 Small Areas. Heights: GSI Open Topographic Data LiDAR (OPW, TII and GSI surveys). Water: EPA river network (rivers of Strahler order 5 or more), lakes, estuaries and coastal waters.

River levels

November 2025 brought the River Little Brosna’s highest day at Croghan since 1961

Each winter’s highest level (October to September) at the OPW’s Croghan gauge, in Birr, since 1961, in metres above the gauge’s zero. Nine days in ten it runs between 0.21 m and 1.66 m.

Each winter’s highest level, metres
Winter 1961–62: highest 1.27 m · 0 days above the normal rangeWinter 1962–63: highest 1.54 m · 0 days above the normal rangeWinter 1963–64: highest 1.56 m · 0 days above the normal rangeWinter 1964–65: highest 1.96 m · 10 days above the normal rangeWinter 1965–66: highest 1.74 m · 4 days above the normal rangeWinter 1966–67: highest 1.80 m · 3 days above the normal rangeWinter 1967–68: highest 1.76 m · 3 days above the normal rangeWinter 1968–69: highest 1.97 m · 11 days above the normal rangeWinter 1969–70: highest 1.46 m · 0 days above the normal rangeWinter 1970–71: highest 1.52 m · 0 days above the normal rangeWinter 1971–72: highest 1.65 m · 0 days above the normal rangeWinter 1972–73: highest 1.61 m · 0 days above the normal rangeWinter 1973–74: highest 1.97 m · 18 days above the normal rangeWinter 1974–75: highest 1.92 m · 5 days above the normal rangeWinter 1975–76: highest 1.53 m · 0 days above the normal rangeWinter 1976–77: highest 1.82 m · 7 days above the normal rangeWinter 1977–78: highest 1.62 m · 0 days above the normal rangeWinter 1978–79: highest 1.98 m · 15 days above the normal rangeWinter 1979–80: highest 1.77 m · 5 days above the normal rangeWinter 1980–81: highest 1.91 m · 2 days above the normal rangeWinter 1981–82: highest 1.78 m · 5 days above the normal rangeWinter 1982–83: highest 1.93 m · 10 days above the normal rangeWinter 1983–84: highest 1.97 m · 16 days above the normal rangeWinter 1984–85: highest 1.84 m · 4 days above the normal rangeWinter 1985–86: highest 2.05 m · 7 days above the normal rangeWinter 1986–87: highest 1.89 m · 9 days above the normal rangeWinter 1987–88: highest 1.95 m · 11 days above the normal rangeWinter 1988–89: highest 1.74 m · 1 days above the normal rangeWinter 1991–92: highest 1.77 m · 2 days above the normal rangeWinter 1992–93: highest 2.06 m · 6 days above the normal rangeWinter 1993–94: highest 1.88 m · 19 days above the normal rangeWinter 1994–95: highest 2.07 m · 38 days above the normal rangeWinter 1995–96: highest 1.88 m · 11 days above the normal rangeWinter 1996–97: highest 1.55 m · 0 days above the normal rangeWinter 1997–98: highest 2.04 m · 18 days above the normal rangeWinter 1998–99: highest 1.92 m · 28 days above the normal rangeWinter 1999–00: highest 2.05 m · 17 days above the normal rangeWinter 2000–01: highest 2.11 m · 30 days above the normal rangeWinter 2001–02: highest 1.97 m · 23 days above the normal rangeWinter 2002–03: highest 1.98 m · 16 days above the normal rangeWinter 2005–06: highest 1.91 m · 4 days above the normal rangeWinter 2006–07: highest 2.12 m · 39 days above the normal rangeWinter 2007–08: highest 2.21 m · 46 days above the normal rangeWinter 2008–09: highest 2.16 m · 16 days above the normal rangeWinter 2009–10: highest 2.23 m · 57 days above the normal rangeWinter 2010–11: highest 2.10 m · 16 days above the normal rangeWinter 2011–12: highest 2.19 m · 60 days above the normal rangeWinter 2012–13: highest 2.10 m · 31 days above the normal rangeWinter 2013–14: highest 2.21 m · 75 days above the normal rangeWinter 2014–15: highest 2.27 m · 45 days above the normal rangeWinter 2015–16: highest 2.32 m on 30 December 2015 · 88 days above the normal rangeWinter 2016–17: highest 2.18 m · 12 days above the normal rangeWinter 2017–18: highest 2.28 m on 22 January 2018 · 74 days above the normal rangeWinter 2018–19: highest 2.21 m · 36 days above the normal rangeWinter 2019–20: highest 2.33 m on 24 February 2020 · 84 days above the normal rangeWinter 2020–21: highest 2.22 m · 73 days above the normal rangeWinter 2021–22: highest 2.22 m · 22 days above the normal rangeWinter 2022–23: highest 2.28 m on 1 November 2022 · 76 days above the normal rangeWinter 2023–24: highest 2.31 m on 24 October 2023 · 119 days above the normal rangeWinter 2024–25: highest 1.97 m · 18 days above the normal rangeWinter 2025–26: highest 2.36 m on 13 November 2025 · 111 days above the normal range’25–26’19–20’15–16Record 2.36 m, 2025Top of normal range
1961–622025–26
The highest days on record
  • 13 November 20252.36 m
  • 24 February 20202.33 m
  • 30 December 20152.32 m
  • 24 October 20232.31 m
  • 30 January 20262.29 m
  • 30 December 20232.29 m

Since 1961 the River Little Brosna has run above its usual top on 1,456 days, most of them in the winters of 2023–24 and 2025–26.

Measured by its highest day, last winter (2025–26) was the highest of the 61 on record here.

Source: OPW Hydro-Data (waterlevel.ie/hydro-data), Croghan gauge (station 25021): 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 Birr

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; Birr is covered by County Offaly’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 Birr can’t be counted here.

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

Flood scheme

No OPW flood relief scheme protects Birr

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 Birr
Protected places in the county
1
Tullamore
Nearest protected place
33 km
Ballinasloe, as the crow flies
Low-lying homes
1.8%
the share a scheme would be built for

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

In County Offaly, an OPW scheme also protects part of Tullamore.

The protected places nearest here
TownSchemeDesigned forHomes behind itAway
Ballinasloe GalwayBallinasloe (Derrymullen) Flood Relief Scheme1 in 1003.2%33 km
Tullamore OffalyTullamore Flood Relief Scheme1 in 1002.4%34 km
Mullingar WestmeathMullingar Flood Relief Scheme1 in 1000.2%61 km
Gort GalwayGort River (Bridge Street) Drainage Scheme1 in 1000.9%61 km
Annacotty LimerickMulkear River (Ballymackeogh) Flood Relief Scheme1 in 101.1%64 km
Kilkenny KilkennyKilkenny City (Nore) Flood Relief Scheme1 in 1002.2%66 km

Official flood maps and past floods: floodinfo.ie

Landslides

No home in Birr 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

BirrCounty Offaly’s medianmedian of Irish towns
High or moderately high0%
0%5%

Birr 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 2.5% of Birr’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.

1.1% of homes estimated above the reference level · 1–5% of homes3% of homes estimated above the reference level · 1–5% of homes0.2% of homes estimated above the reference level · Under 1% of homes0% of homes estimated above the reference level · Under 1% of homes1.2% of homes estimated above the reference level · 1–5% of homes2% of homes estimated above the reference level · 1–5% of homes2.3% of homes estimated above the reference level · 1–5% of homes0.1% of homes estimated above the reference level · Under 1% of homes2.5% of homes estimated above the reference level · 1–5% of homes0% of homes estimated above the reference level · Under 1% of homes1.2% of homes estimated above the reference level · 1–5% of homes© OpenStreetMap contributors · EPA
Under 1% of homes1–5% of homes
Share of Irish towns in each band
Under 1% of homes17%
1–5% of homes · Birr38%
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 Birr’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
2.6%
County Offaly’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

One EPA-licensed site within 5 km of Birr’s centre, none inside it

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

0
licensed sites inside Birr
1
licensed site within 5 km of the centre
2.0 km
to the nearest: Grant Engineering (Ireland) Unlimited Company
The 2 nearest licensed sites
SiteLicence and activityAway
Grant Engineering (Ireland) Unlimited CompanyIndustrial Emissions licence · solvents and coatings2.0 km
Rosderra Farms Unlimited CompanyIndustrial Emissions licence · intensive farming9.0 km
What the 2 licensed sites within 10 km do
ActivitySites
Solvents and coatings1
Intensive farming1

Within 5 km: one under an Industrial Emissions licence.

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 Birr

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

BanagherKilcormacRoscreaBorrisokaneBanagherKilcormacRoscreaBorrisokaneBirr
TownLow-lyingRadonLandslides
Birr1.8%2.5%0%
Banagher
1,907 · 12 km		–0.2%0%
Kilcormac
1,051 · 15 km		0%1.2%0%
Roscrea
5,542 · 17 km		0%0.2%0.3%
Borrisokane
1,117 · 18 km		0%2%0%

Birr has more of its homes standing low by big water than any measured place around it; the next is Kilcormac (0%).

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

Be ready

Get ready for what Birr 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 Birr
  • 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 Birr

Does Birr flood?

Smaller streams, drains and groundwater aren’t in that measure, so it doesn’t mean the town never floods. For a single address, the OPW’s official flood maps and past floods are on floodinfo.ie.

Is radon a problem in Birr?

The EPA’s map estimates that about 2.5% of homes around Birr are above the radon reference level of 200 Bq/m³: a lower share than in 68% 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 Birr at risk of landslides?

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

Is Birr at risk from the sea?

None of Birr’s homes stands below 4 m within 2 km of the sea, so the sea plays no part in its share of low-lying homes; 1.8% stand low by rivers, lakes and estuaries.

How does Birr compare with the places around it?

Radon estimates around Birr run from 0.2% in Banagher to 2% in Borrisokane; Birr’s own is 2.5%.

How is Birr’s Hazard risk Grade worked out?

Birr grades B+: radon, landslide ground and low-lying homes are each placed among Irish towns, and the grade averages them.

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 · the grade: TownRatings, from these figures. 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).