Is the house in a flood zone? How to check flood risk and drainage for an Irish address
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To check flood risk for an Irish address, search the address on floodinfo.ie, the OPW's flood map service. It shows predicted river and coastal flood extents and records of past floods. Then look at the flood zone maps in the council's development plan: Zone A is high probability, Zone B moderate, Zone C low. The maps are community-level, not an assessment of one house, so also read the estate's drainage plan and get an insurance quote early.
The two maps to check
1. The OPW flood maps on floodinfo.ie. The Office of Public Works publishes maps of possible flooding "from rivers (fluvial flooding) and from extreme sea levels (coastal flooding)", plus the location of known past flood events (floodinfo.ie).
2. The council's flood zone maps. Councils publish a Strategic Flood Risk Assessment with their development plan, with maps of Flood Zones A, B and C. Dublin City's, for example, sits alongside the Dublin City Development Plan 2022 to 2028 (Dublin City Council SFRA). Local area plans may have their own.
Check both. The OPW maps show where flooding could reach. The council's flood zones are used when planning applications on that land are assessed.
How to use floodinfo.ie, step by step
- Open the flood maps viewer.
- Type the address or place into the location search, or zoom in on the map. The search does not find every Eircode, and a brand-new estate may not be found at all, so if it fails, zoom to the spot instead.
- Turn on the river (fluvial) and coastal flood extent layers. Each shows the area that could flood in an event of a given probability.
- Turn on past flood events. Click any marker near the home to read the report, which may include photos and press cuttings.
- Note whether the home, the road into the estate, and the land around it fall inside any extent.
A word on probability. A "1% chance" or "1 in 100" flood means a 1 in 100 chance of that flood in any single year. It does not mean once a century.
Flooding from heavy rainfall on streets and hollows (pluvial flooding) is mapped only for some places, such as Dublin City and Raphoe in Donegal (floodinfo.ie). Elsewhere, the absence of a rainfall layer does not mean there is no risk.
Flood Zones A, B and C in plain English
The flood zones come from national planning guidelines, The Planning System and Flood Risk Management (2009), paragraph 2.23 (guidelines, hosted by the Office of the Planning Regulator):
| Zone | Probability of flooding from rivers and the sea | In plain English |
|---|---|---|
| Flood Zone A | Highest: more than 1% a year (1 in 100) from rivers, or more than 0.5% a year (1 in 200) from the sea | High probability |
| Flood Zone B | Moderate: between 0.1% (1 in 1,000) and 1% from rivers, or between 0.1% and 0.5% from the sea | Moderate probability |
| Flood Zone C | Low: less than 0.1% a year (1 in 1,000) | Low probability |
Zone C does not mean no risk. It means the risk from rivers and the sea is low. The guidelines say the zones cover river and coastal flooding only, and "do not include the effects of other forms of flooding such as from groundwater or artificial drainage systems" (paragraph 2.26).
New estates: the flood risk assessment and the drainage plan
For a new home, the estate's planning file is the most detailed source you have. In the file, look for:
- A site-specific flood risk assessment, where one was filed. It looks at flood risk for that site in more detail than the national maps, and may set floor levels for the houses.
- An engineering or drainage report and drainage drawings. These show how rainwater and wastewater leave the estate.
- The SuDS design. Sustainable drainage systems slow and store rainwater, using features such as swales, filter drains, detention basins and attenuation ponds (South Dublin County Council).
- The planner's report and conditions, which may record what the council's drainage engineers asked for.
Our guide to finding the planning file and drawings shows how to find the estate's permission. If a new scheme is planned next door, check its drainage report too: see what's planned near a new home.
What the maps do not show
Be clear about what the maps are for. The OPW says: "The purpose of the Flood Maps is not to designate individual properties at risk of flooding. They are community-based maps." It also says "there is always some uncertainty" in predictive flood models (floodinfo.ie).
A reply to a buyer asking how to assess flood risk called floodinfo.ie "an extremely loose guide" (Askaboutmoney, 17 Mar 2025). That is fair for a single house. The maps are a starting point, not the answer.
Very local issues, such as a low corner of a garden or a road that ponds after heavy rain, will not appear on a national map. For an existing home, ask the seller. For a new build, read the drainage design and ask the developer.
Insurance and your mortgage
Flood risk can matter for insurance, and insurance can matter for your mortgage.
One buyer, sale agreed in Cork city centre, found their lender would not release the mortgage until home insurance with full cover, including flood, was in place. Online quotes declined flood cover for the Eircode (Askaboutmoney, 20 Dec 2025). The practical lesson: get a home insurance quote, including flood cover, for the Eircode early, well before closing.
Where the OPW has completed a flood defence scheme, a Memorandum of Understanding agreed in 2014 between the OPW and Insurance Ireland "requires that insurers take full account" of information on the scheme. It "does not guarantee the availability of flood risk cover" (floodinfo.ie, OPW). Cover and price remain each insurer's decision.
Whether you can get cover, and on what terms, is a question for an insurer or insurance broker. Whether your lender will accept it is a question for your lender or mortgage broker.
Questions to ask
The developer or selling agent
- Is there a site-specific flood risk assessment for the estate? Can I see it?
- How is the estate drained, and where does the SuDS system discharge?
Your solicitor
- Does anything in the contract or the planning file mention flooding or drainage issues?
Your insurer or broker
- Will you offer home insurance including flood cover for this Eircode?
- Are there any exclusions or excesses for flood?
For the rest of the checks on a new build, see buying a new build or off-plan home in Ireland.
Where PropertyBuddy fits
Flood risk and drainage are part of every PropertyBuddy report (Essential). We read the published flood information for the area and the estate's drainage and runoff plans, and set out what they show in plain English. The report does not say whether an insurer will cover the home or a lender will lend, and it cannot say a home will never flood. Those questions stay with your insurer and lender.