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CHazard risk Grade
Flood & hazards in Summerhill · EPA, GSI and OPW data

41% of Summerhill’s homes stand on low ground beside the Liffey Estuary: more than in 92% of Irish towns

Hazard risk puts Summerhill at C, #105 of 116 in County Dublin. Radon, landslide ground and its low-lying homes all count, and the low-lying homes pull it down.

In brief

What stands out about Summerhill’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.

By hazard

What Summerhill faces

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

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

Hazard risk in Summerhill: C

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

Radon (3.8%)Better than 55% of Irish towns
Landslide ground (0%)Better than 57% of Irish towns
Low-lying homes (41%)Better than 6% 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 Summerhill’s share of low-lying homes is high enough to lower its grade.

Its place: #105 of 116 in County Dublin and #228 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

41% of Summerhill’s homes stand low beside the Liffey Estuary

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.

By a river, lake or estuary41%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 Summerhill sits among 231 Irish towns
43%None
6%Under 0.5%
4%0.5–1%
7%1–2%
8%2–5%
6%5–10%
8%10–20%
18%20% +Summerhill

Share of each town’s homes standing low by big water, for the towns measured in detail. 43% have none; Summerhill has more than 92% of them.

Towns its size: 37th of 40, from the fewest low-lying homes
#TownPeopleLow-lying
1Cabra East Dublin13,8950%
2Knocklyon Dublin13,8540%
3Deansrath Dublin13,7430%
…
35Parnell Square Dublin10,11723%
36Drumcondra Dublin11,14929%
37Summerhill Dublin11,91141%
38Dungarvan Waterford10,08144%
39Ballsbridge Dublin12,74355%
40Shannon Clare10,25690%

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

978
homes counted
~400
homes standing low by big water
0%
County Dublin’s median
0.7%
median of Irish towns

Low-lying homes across County Dublin’s towns · 106 towns measured in detail

O'Connell Street100%
East Wall100%
Sandymount86%
Baldoyle77%
Sutton75%
Ballybough67%
Ballsbridge55%
Summerhill41%

Summerhill ranks 9th of County Dublin’s 106 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.

Warnings

Weather and flood warnings for Summerhill

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; Summerhill is covered by County Dublin’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 Summerhill can’t be counted here.

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

Flood scheme

No OPW flood relief scheme protects Summerhill

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 Summerhill
Protected places in the county
12
Dublin, Clonsilla, Sandymount, Mulhuddart, East Wall
Nearest protected place
0.7 km
Ballybough, as the crow flies
Low-lying homes
41%
the share a scheme would be built for

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

In County Dublin, OPW schemes protect parts of 12 other places, including Dublin, Clonsilla, Sandymount, Mulhuddart, East Wall.

The protected places nearest here
TownSchemeDesigned forHomes behind itAway
Ballybough DublinRiver Tolka ( Dublin) Flood Relief Scheme1 in 10022%0.7 km
East Wall DublinSpencer Dock Flood Relief Scheme1 in 20082%1.3 km
St Stephen's Green DublinSouth Campshires Flood Relief Scheme1 in 2005.9%1.4 km
Grand Canal Dock DublinSouth Campshires Flood Relief Scheme1 in 20014%1.6 km
Drumcondra DublinRiver Tolka ( Dublin) Flood Relief Scheme1 in 10015%1.7 km
Glasnevin DublinRiver Tolka ( Dublin) Flood Relief Scheme1 in 1001.8%1.9 km

Official flood maps and past floods: floodinfo.ie

Landslides

No home in Summerhill 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

SummerhillCounty Dublin’s medianmedian of Irish towns
High or moderately high0%
0%5%

Summerhill 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 3.8% of Summerhill’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.

1.7% of homes estimated above the reference level · 1–5% of homes7.5% of homes estimated above the reference level · 5–10% of homes0% of homes estimated above the reference level · Under 1% of homes5.5% of homes estimated above the reference level · 5–10% of homes3.8% of homes estimated above the reference level · 1–5% of homes0% of homes estimated above the reference level · Under 1% of homes0% of homes estimated above the reference level · Under 1% of homes5.1% of homes estimated above the reference level · 5–10% of homes0% of homes estimated above the reference level · Under 1% of homes1.6% of homes estimated above the reference level · 1–5% of homes0% of homes estimated above the reference level · Under 1% of homes0% of homes estimated above the reference level · Under 1% of homes© OpenStreetMap contributors · EPA
Under 1% of homes1–5% of homes5–10% of homes
Share of Irish towns in each band
Under 1% of homes17%
1–5% of homes · Summerhill38%
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 Summerhill’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
3.8%
County Dublin’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

25 EPA-licensed sites within 5 km of Summerhill’s centre, none inside it

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

0
licensed sites inside Summerhill
25
licensed sites within 5 km of the centre
0.8 km
to the nearest: Independent Newspapers Ltd.
The 8 nearest licensed sites
SiteLicence and activityAway
Independent Newspapers Ltd.Industrial Emissions licence0.8 km
Lower Oriel StreetWaste licence0.9 km
Mater Misericordiae University HospitalIndustrial Emissions licence · waste1.0 km
Sita Environmental Ltd.Waste licence1.3 km
Cahill Printers LimitedIndustrial Emissions licence1.5 km
Everlac Paints LtdIndustrial Emissions licence1.6 km
Brooks Thomas LimitedIPC licence1.7 km
Dean Waste Company Ltd (Upper Sheriff Street)Waste licence1.7 km
What the 95 licensed sites within 10 km do
ActivitySites
Not classed in the register34
Waste34
Energy15
Food and drink4
Chemicals4
Metals3
Solvents and coatings1

Within 5 km: 15 under Industrial Emissions licences, 6 under older IPC licences and 4 waste facilities.

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 Summerhill

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

Parnell SquareBallyboughO'Connell StreetPhibsboroughEast WallSt Stephen's GreenParnell SquareBallyboughO'Connell StreetPhibsboroughEast WallSt Stephen's GreenSummerhill
TownLow-lyingRadonLandslides
Summerhill41%3.8%0%
Parnell Square
10,117 · 0.4 km
23%3.8%0%
Ballybough
8,188 · 0.7 km
67%3.8%0%
O'Connell Street
6,749 · 0.9 km
100%3.8%0%
Phibsborough
11,657 · 0.9 km
3.8%3.8%0%
East Wall
15,907 · 1.3 km
100%3.8%0%
St Stephen's Green
5,319 · 1.4 km
38%3.8%0%

Of the places around Summerhill, O'Connell Street has the most homes standing low by big water (100%), 0.9 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 Summerhill 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 Summerhill
  • 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 Summerhill

Does Summerhill flood?

About 41% of Summerhill’s homes stand low beside the Liffey Estuary: a higher share than in 92% of Irish towns. That is our estimate from ground heights, not an official flood map. For a single address, the OPW’s official flood maps and past floods are on floodinfo.ie.

Is radon a problem in Summerhill?

The EPA’s map estimates that about 3.8% of homes around Summerhill are above the radon reference level of 200 Bq/m³: a lower share than in 59% 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 Summerhill at risk of landslides?

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

Is Summerhill at risk from the sea?

None of Summerhill’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; 41% stand low by rivers, lakes and estuaries.

How does Summerhill compare with the places around it?

Radon estimates around Summerhill run from 3.8% in East Wall to 3.8% in St Stephen's Green; Summerhill’s own is 3.8%. Among the places measured in detail, O'Connell Street has the largest share of homes standing low (100%).

Where is the nearest bathing water to Summerhill?

Sandymount Strand, 4.6 km away, was rated sufficient for the 2025 season; 11 identified bathing waters lie within 15 km.

How is Summerhill’s Hazard risk Grade worked out?

Summerhill grades C: 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 · bathing water: EPA bathing water quality · 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).