Flood Data Sources: Where Our Environment Agency, NRW, SEPA And DfI Data Comes From

Flood Risk Checker uses flood risk, Flood Zone, river level and warning data published by the Environment Agency, Natural Resources Wales and SEPA under the Open Government Licence, with postcode and settlement data from Ordnance Survey and the Office for National Statistics.

Each dataset is listed below with its publisher, licence, a link to the original and the date we last checked it. How we turn these datasets into place figures is explained in our methodology.

floodriskchecker.co.uk is an independent website. It is not run by, or affiliated with, the Environment Agency, Defra, SEPA, Natural Resources Wales or any government body.

Which Environment Agency Datasets Does This Site Use?

This site uses eight Environment Agency datasets for England: two flood risk datasets, two Flood Map for Planning datasets, a postcode summary of properties at risk, two records of past floods and warnings, and the real-time flood-monitoring API. All are published under the Open Government Licence.

Dataset	What it provides	Licence	Last checked
Risk of Flooding from Rivers and Sea	Flood risk band for rivers and the sea; it shows the chance of flooding from rivers and the sea taking into account the presence and condition of flood defences	OGL v3.0	18 Sept 2026
Risk of Flooding from Surface Water	Flood risk band for surface water	OGL v3.0	18 Sept 2026
Flood Map for Planning – Flood Zones	Flood Zones 2 and 3: the extent of land at present day risk of flooding from rivers and the sea, ignoring the benefits of defences	OGL v3.0	18 Sept 2026
Flood Map for Planning – Flood Zones plus Climate Change	how the combined extent of Flood Zones 2 and 3 could increase with climate change over the next century, ignoring the benefits of any existing flood defences	OGL v3.0	18 Sept 2026
Risk of Flooding from Rivers and Sea – Postcodes in Areas at Risk	a summary of properties at risk of flooding from rivers and the sea at a postcode scale, including a breakdown by flood risk likelihood category and property type	OGL v3.0	18 Sept 2026
Recorded Flood Outlines	all our records of historic flooding from rivers, the sea, groundwater and surface water, from 1946	OGL v3.0	18 Sept 2026
Historic Flood Warnings	Severe Flood Warnings, Flood Warnings and Flood Alerts issued since the flood warning system went live on January 26th 2006	OGL v3.0	18 Sept 2026
Real-time flood-monitoring API	Flood warnings and alerts, monitoring stations and readings	OGL v3.0	20 Sept 2026

The flood-monitoring API's list of current warnings is updated every 15 minutes, and its readings cover up to the last four weeks.

Which Welsh, Scottish And Northern Irish Datasets Does This Site Use?

For Wales and Scotland, this site uses the flood maps published by Natural Resources Wales and SEPA, both under the Open Government Licence. For Northern Ireland, DfI's own flood maps are licensed commercially rather than openly, so this site describes Flood Maps NI and links to it instead of republishing its data — but Northern Ireland figures on this site are not blank: they come from two other sources instead, one open and one published under a disclosed risk-acceptance rather than an open licence (see below).

Nation	Dataset	Licence	Last checked
Wales	Flood Map for Planning: River, Sea, and Surface Water and Small Watercourses Flood Zones	OGL
Wales	Flood Risk Assessment Wales	OGL
Scotland	SEPA Flood Maps v3.0 — river, coastal and surface water extents, High/Medium/Low likelihood	OGL v3.0	18 Sept 2026
Scotland	SEPA National Flood Risk Assessment — homes at risk, counted per settlement	OGL v3.0	18 Sept 2026
Northern Ireland	Flood Maps NI — DfI's official map, viewed and linked, not republished	Commercial licence through Land & Property Services	—
Northern Ireland	CEMS-EFAS river flood hazard — a modelled substitute for DfI's map, used because DfI's own map is not open	CC BY 4.0 (European Union)	—
Northern Ireland	NISRA Settlement Development Limits 2015 — the 527 named places used as this site's Northern Ireland towns	OGL	—

Welsh Flood Zones are updated in late May and late November each year. SEPA's flood hazard maps were last updated 30 January 2025 (v3.0).

A note the other rows above do not need. This site also uses Northern Ireland's own "BT" postcodes, sourced from the Office for National Statistics' UK postcode products, to power the postcode checker there. That is not an open dataset for Northern Ireland specifically — see the next section.

Which Postcode And Geography Datasets Does This Site Use?

This site uses Ordnance Survey and Office for National Statistics datasets to locate postcodes, define towns and estimate the number of homes in each postcode. These datasets contain no flood information; they decide which flood data belongs to which place.

Dataset	Publisher	Used for	Licence	Last checked
Code-Point Open	Ordnance Survey	Postcode centre points	OGL	18 Sept 2026
OS Open Rivers	Ordnance Survey	Named rivers and streams	OGL	18 Sept 2026
ONS Postcode Directory	Office for National Statistics	England, Wales and Scotland postcodes: OGL. Northern Ireland postcodes: published under this site's own risk-acceptance, not OGL — see below	OGL (E/W/S) · owner risk-acceptance (NI)	18 Sept 2026
Built-up areas	Office for National Statistics	The boundary of each English and Welsh town	OGL	18 Sept 2026
Census 2021 household counts	Office for National Statistics	Estimated homes per postcode, England and Wales	OGL	18 Sept 2026
NRS Census 2022	National Records of Scotland	Counted (not estimated) households per postcode and Scotland's 656 towns	OGL v3.0

Which Sources Are Used For Facts In Articles?

Facts in articles, such as planning rules, insurance scheme figures and national statistics, come from the publisher's own page or document, and each article lists its sources with the date they were verified. The main publishers are listed below.

Topic	Primary sources
Planning in England	National Planning Policy Framework; Planning Practice Guidance; GOV.UK flood risk assessment guidance
Planning in Wales, Scotland and Northern Ireland	Natural Resources Wales; Scottish Government (National Planning Framework 4); Department for Infrastructure (Revised PPS 15)
National statistics	Environment Agency national assessment; Natural Resources Wales annual report; SEPA flood risk management plans; DfI Northern Ireland Flood Risk Assessment
Insurance	Flood Re; Association of British Insurers; British Insurance Brokers' Association
Law	legislation.gov.uk
Warnings and reporting	GOV.UK; Natural Resources Wales; SEPA; NI Direct

What Attribution Does This Site Give?

This site gives the attribution required by the Open Government Licence v3.0 on every page, together with each publisher's own copyright statement for the datasets that require one.

On every page:

Contains public sector information licensed under the Open Government Licence v3.0. Flood risk and river level data supplied by the Environment Agency, Natural Resources Wales and the Scottish Environment Protection Agency.

Publisher statements:

The full licence is published at nationalarchives.gov.uk/doc/open-government-licence/version/3.

Northern Ireland is not covered by the OGL sentence above — two different statements apply, and neither is optional:

Contains information from Land & Property Services, reproduced under a Crown copyright licence.

Flood data derived from the EU's Copernicus Emergency Management Service (CEMS-EFAS), © European Union, licensed under Creative Commons Attribution 4.0 International. The figures on this site are a modelled estimate classified into risk bands, not a direct extract of the source depth data — that classification is this site's "indication of changes", which CC BY 4.0 requires alongside credit.

The Land & Property Services line is not, on its own, a claim that this site's use of NI postcode data is licensed in the ordinary sense. It is not — see what data does this site use for Northern Ireland above and the build note below for the full finding. Questions about this go to editor@floodriskchecker.co.uk.