What are Überschwemmungsgebiete?
Überschwemmungsgebiete are flood plains formally designated under §76 of the German Federal Water Act (Wasserhaushaltsgesetz, WHG): areas that statistically flood at least once in a hundred years or are needed for flood retention. Designation happens by state ordinance and makes the boundary legally binding, and §78 WHG attaches building bans and permit requirements to it. This layer unifies the officially published designations of 13 German states into one queryable dataset.
How legally binding are Überschwemmungsgebiete?
Legal status
Legally binding
This designation has direct legal effect. It can permit or prevent what you build on a site.
Festgesetzte Überschwemmungsgebiete are designated by state ordinance under §76 WHG. The designation is a binding legal act, not a modelling result: authorities, courts, and permitting procedures work from exactly these boundaries.
What this means for you
Inside designated areas, §78 WHG prohibits the designation of new development zones and makes new construction subject to permits, typically with conditions such as flood-adapted building and compensation of lost retention volume. For provisionally secured areas (vorläufig gesichert), the same regime applies accordingly.
What attributes do the Überschwemmungsgebiete data include?
Designation status
Whether an area is festgesetzt (formally designated) or vorläufig gesichert (provisionally secured), where the state publishes this distinction.
Name and waterbody
The name of the designation and, where published, the river or waterbody the flood plain belongs to.
Geometry
Area polygons of the designated boundary, delivered as published by the state.
Bundesland
The source state of each designation, for provenance and state-specific legal follow-up.
The legal basis is federal, the implementation is state-specific: naming conventions, attribute depth, and how the distinction between festgesetzt and vorläufig gesichert is published differ between the 13 covered states. We harmonise structure and format while preserving each state's original designation content, so every feature stays traceable to its official source.
What are Überschwemmungsgebiete data used for?
- Portfolio screening: intersect all holdings with designated flood plains and flag §78-restricted parcels in a single query.
- Transaction due diligence: document whether a target property lies inside a festgesetztes Überschwemmungsgebiet, with the designation status as evidence.
- Insurance and lending: distinguish legally designated flood plains from modelled hazard when assessing collateral and exposure.
- Site selection and planning: detect binding building restrictions before design work, permitting budgets, or land negotiations begin.
Where do the Überschwemmungsgebiete data come from?
Sourced from the official geoportals and water authorities of the German states, the same designations that permitting authorities work from.
Which German states do the Überschwemmungsgebiete cover?
Available for 13 of 16 German states. Baden-Württemberg, Bavaria and Saxony-Anhalt do not publish designated Überschwemmungsgebiete at source. Where the state publishes them, we carry them, without filling gaps with estimates.
Coverage by federal state
- BBBrandenburgAvailable
- BEBerlinAvailable
- BWBaden-WürttembergNot published by the state
- BYBavariaNot published by the state
- HBBremenAvailable
- HEHesseAvailable
- HHHamburgAvailable
- MVMecklenburg-Western PomeraniaAvailable
- NILower SaxonyAvailable
- NWNorth Rhine-WestphaliaAvailable
- RPRhineland-PalatinateAvailable
- SHSchleswig-HolsteinAvailable
- SLSaarlandAvailable
- SNSaxonyAvailable
- STSaxony-AnhaltNot published by the state
- THThuringiaAvailable
Where the federal state publishes this layer, we carry it: 13 of 16 federal states today. Where it doesn't, we say so.
Coverage gap
Your region of interest isn't covered?
Coverage follows what each state and municipality has actually digitised, so there are real gaps, and they are not always where you would expect. Tell us the region and the layer you need and we will look into what can be sourced for it, including data we do not list today.
Tell us what you needHow do you get Überschwemmungsgebiete as GIS data?
One unified dataset: Ready for direct integration into your GIS, CAD, or BI tools. Standard formats, documented schema.
Mapular Explorer: Instant planning interface, no GIS setup required. Filter, analyse, and export from your browser.
Frequently asked questions about Überschwemmungsgebiete
What is the difference between Überschwemmungsgebiete and Hochwassergefahrenflächen?
Überschwemmungsgebiete are legally designated flood plains under §76 WHG, and their boundaries carry binding building restrictions under §78 WHG. Hochwassergefahrenflächen come from the flood hazard maps of the EU Floods Directive: they show, scenario by scenario, how far a flood of a given probability could reach, but they are informational, not a legal designation. For thorough risk screening you typically want both layers.
Can you build in a designated Überschwemmungsgebiet?
In festgesetzte Überschwemmungsgebiete, §78 WHG prohibits the designation of new development areas and places new construction under a strict permit requirement. Exceptions exist but must be individually approved by the water authority, typically with conditions such as flood-adapted construction and compensation of lost retention volume. A parcel inside a designated flood plain is therefore a material due-diligence finding, not a formality.
Why does the dataset cover 13 of 16 German states?
Baden-Württemberg, Bavaria and Saxony-Anhalt do not publish their designated Überschwemmungsgebiete at source. Where a state publishes the designations, we carry them, so the layer covers the 13 states that do. We state this openly rather than filling gaps with estimates, because a legally binding layer must remain traceable to the official designation.
What does 'festgesetzt' versus 'vorläufig gesichert' mean?
Festgesetzt means the flood plain has been formally designated by ordinance and the restrictions of §78 WHG fully apply. Vorläufig gesichert means the area has been provisionally secured pending formal designation, and during that interim period the requirements of §78 WHG apply accordingly. Where states publish the designation status, it is included as an attribute in the layer.
Why use queryable GIS data instead of the state map viewers?
Each German state publishes its designations in its own map viewer, with its own interface, projection, and attribute names. Checking a nationwide portfolio that way means sixteen separate lookups per screening round. As one harmonised layer, you can intersect every site with the designated boundaries in a single query, keep the results as documented evidence, and repeat the check whenever your portfolio changes.
How do I check whether a specific property lies in an Überschwemmungsgebiet?
Intersect the property geometry (parcel, address point or building footprint) with the designated flood-plain polygons. Because Überschwemmungsgebiete are published as binding boundaries, the result is a clear in/out answer per site rather than a probability estimate. For transactions, export the intersection result as documentation. For portfolios, run the same query across all holdings at once.