Legal Question in Real Estate Law in California

Re: Tenants in Common - right to possesion without paying rent

Tenants in common (or joint tenants) have what is called an "undivided right of possession" in the co-owned property. The result is that all co-owners can occupy and use every square inch of the co-owned property without owing rent to the other(s).

There are exceptions. First, the rights of co-owners can be modified by contract. The contract can be written or oral, express or implied. A possible limitation on this is that any agreement intended to last more than a year would have to be in writing under the Statute of Frauds.

The other exception is that a co-owner cannot derive income from third parties without being obliged to share that income with the others. For example, if X and Y co-own Blackacre, and X leases Blackacre to Z, Y is entitled to half (or whatever his share of ownership is) of the net profit from the leasing activity.

These are general rules only, and a lot of case-law interpretations and modifications exist to complicate matters. In your particular example, it may be necessary to inquire into the nature of the trusts and whether the beneficiaries are being cheated as a result of a trustee living in trust property. Of course, if the resident trustee is also the sole beneficiary of that trust, there wouldn't seem to be a problem (but one would have to read the trust to be certain).