Just before breaking for the summer, Berlin’s state parliament passed the Housing Security Act (Wohnraumsicherungsgesetz). It creates something Germany hasn’t had before: a central digital register of homes and rents, covering every tenancy in the city, roughly 1.8 million of them (berlin.de, 2026).
What has to be reported
The law requires nine details for each apartment (Mietervereinigung Berlin, 2026):
| No. | Detail | Where it lives | Effort |
|---|---|---|---|
| 01 | the full address | lease | In the file |
| 02 | floor area, room layout, and basic amenities | floor-area calculation | In the file |
| 03 | the landlord's name and address | land register extract | In the file |
| 04 | the number of household members | ask the tenant | Not yet recorded |
| 05 | date and type of any social-housing entitlement certificate (WBS) | WBS copy in the tenant file | In the file |
| 06 | start and agreed duration of the tenancy | lease | In the file |
| 07 | net cold rent plus prepayments for service charges, heating, and water | lease plus the last increase | To calculate |
| 08 | any modernization surcharges | modernization notice | In the file |
| 09 | the apartment's share of the property tax | tax assessment and co-ownership share | To calculate |
The register won’t be public. It’s built for the authorities, who want to check whether rents sit above the legal limits.
Deadlines and fines
First registration is due within twelve months of the register going into regular operation, expected during 2027. Changes to reported data have to be updated within one month. Violations carry fines of up to €10,000, rising to €100,000 for repeat cases or a substantial number of apartments. That upper bracket is aimed squarely at owners with a portfolio.
Berlin Housing Security Act, passed July 2026 · filing route to follow by regulation
What’s still open is the filing route: the portal, interface, and data formats come in an implementing regulation that hasn’t been published yet. What the law already fixes: bulk upload will be available for larger portfolios, and an authorized agent may file on the landlord’s behalf. We’re tracking the rollout and will update this post once the route is set.
Nine fields, one reporting date
Address, area, rent sounds manageable. Per unit, across a whole portfolio, the maths looks different. The floor area is buried in a lease somewhere in a binder. Today’s rent is the original lease plus every increase since, assuming each one was actually put in writing. Almost no owner has ever recorded household members per apartment, and the property-tax share per unit is a calculation out of the tax assessment and the co-ownership share.
That makes a register filing the same exercise as the year-end tenant schedule your bank asks for: one cut-off date, every unit, evidence behind every number. Just with more fields, a statutory deadline, and a fine attached. If you already have that discipline, the filing is an export. If you don’t, it becomes a project, and Berlin will be the one setting the deadline.
What you can do now
Keep the nine details in one place for every unit, with the paperwork behind each one: the lease, the last rent increase, the floor area calculation, the property-tax assessment. Your bank already asks for this data. So does your accountant, and so will a buyer. The register simply adds one more name to that list, this time with a deadline.
EstateMate already helps owners generate and submit the right reports at the right time: the tenant schedule, the property report, the portfolio report, each figure backed by its document. Once Berlin settles the filing route, the register becomes one more report on that list.
