Registers
BAG (Kadaster)
The Dutch Registry of Addresses and Buildings records which addresses and buildings exist in the Netherlands. Municipalities are the data holders: they enter the records and are responsible for their quality. The Kadaster operates the national facility and supplies the data to users. The registry has seven object types: place of residence, public space, address designation, dwelling unit, pitch, mooring and building. We query the Kadaster's official object-level API.
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What this source does not give you
The address-and-buildings registry says nothing about ownership. Who owns a property, what mortgage rests on it and whether it is under attachment are not in this registry but in the public registers and the cadastral registry — a separate registration with its own supply and pricing regime. Nor does it hold residents (that is the population register), property-tax valuations, cadastral parcel boundaries or permit files.
Legal domains for which LEO consults this source
Dutch legal domains; each link opens the domain page on leo.prudai.com.
Frequently asked questions
- Can I see who owns a building from this registry?
- No. Ownership, mortgages and attachments belong to the cadastral registry and the public registers, not to the address-and-buildings registry. The public registers hold the registered notarial deeds on registered property; the key data from those — ownership, property rights and, since 1995, mortgages and attachments — appear per parcel in the cadastral registry. That is a different source and a different request.
- Which fields do I get per object?
- For a building: the original construction year, its status and whether it was recorded on observation. For a dwelling unit: intended uses, floor area, status and which building or buildings it belongs to. For a public space: name, type and status; for a place of residence: name and status. Every object carries a nationally unique identifier.
- What does it mean when an object is marked as 'observed'?
- That the object was entered in the registry following an actual observation, without a regular source document being available at that moment. It expressly does not mean unlawful: an observed object may later prove to be perfectly legal, for instance because it is permit-free. It is a prompt to look further, not a judgment.
- Is the cadastral parcel part of this registry?
- No. Parcel numbers and parcel boundaries belong to the cadastral registry and the cadastral map, not to the address-and-buildings registry, which describes addresses and built objects. The link between a dwelling unit and a parcel runs through the cadastral registry.
- What if an address or construction year is wrong?
- Then it is for the municipality to act. Municipalities are the data holders of this registry and are responsible for entering the records and for their quality; the Kadaster operates the national facility and passes on what the data holder recorded. A correction therefore runs through the municipality, not through the data user.