Nebenkosten in a Two-Person Apartment: Who's Liable If Payments Stop?

When two people move into an apartment together, the question of how rent and Nebenkosten get split if there's a dispute comes up quickly. The answer depends entirely on who actually signed the rental contract.

Both names on the contract mean full liability for each person

If both residents are listed as tenants on the Mietvertrag, § 427 BGB applies: when several people jointly commit by contract to a divisible obligation, they're presumed to be jointly and severally liable. For rent and Nebenkosten, that means the landlord can demand the full amount from either person individually, not just their calculated half. If one person doesn't pay their share, the landlord can claim the entire outstanding amount from the other name on the contract.

What that means day to day

This rule mainly protects the landlord, not the flatmates or partners between themselves. If one of them moves out or runs into financial trouble, the other remains fully responsible to the landlord for the entire Warmmiete and any Nebenkosten Nachzahlung, regardless of whatever internal split the two of them had agreed on.

Only one person on the contract: a different starting point

If only one person is listed as tenant while the second moves in without their own tenancy status, only the person named in the contract is liable to the landlord for rent and Nebenkosten. Any internal arrangement to split costs is purely a private matter between the two residents and has no legal relevance for the landlord.

Why a written internal agreement still makes sense

Even though § 427 BGB governs liability toward the landlord, it's worth putting the internal cost split in writing — an email or a short shared note is enough. That creates clarity if disagreement later arises over payments already made, or over a Nachzahlung from the Nebenkostenabrechnung.

What matters if one person moves out

If one of the two moves out, joint and several liability toward the landlord continues as long as the rental contract itself hasn't been formally changed, for example through an amendment or a termination the landlord agrees to. Simply moving out without a contract change doesn't automatically release anyone from future rent and Nebenkosten obligations.

If you're planning to move in together and want a fuller picture of what monthly costs actually look like, see our Nebenkosten examples by household size. And if you want to understand how landlords are legally allowed to split those costs between tenants in general, check our guide on square meter vs. person-based billing.

Frequently Asked Questions

If both partners are on the rental contract, are they each only liable for half the Nebenkosten?

No, under § 427 BGB both are jointly and severally liable for the full amount; the landlord can demand the entire sum from either person.

What happens if only one person is listed on the rental contract?

Then only that person is liable to the landlord; any internal cost split with a roommate is a private matter with no legal effect on the landlord.

Does liability continue after one person moves out?

Yes, as long as the rental contract hasn't been formally amended, joint and several liability for rent and Nebenkosten toward the landlord continues.

Should we put our internal cost split in writing?

It's a good idea, to avoid later disputes over payments already made or a Nebenkosten Nachzahlung, even though it has no legal effect on the landlord.