Legal Question in Real Estate Law in California

There is a set of legal principles that govern the rights and duties of co-owners of real estate. Most of them can be varied by private contract between the co-owners, but in the absence of such an agreement, here are the rules:

First, the law does not recognize the concept of "my half" and "her half." All co-owners are entitled to shared, joint possession of every square inch of the property.

Next, neither co-owner is expected to pay, or entitled to charge, rent to/from the other, even when one is currently out of possession.

However, net rents (after out-of-pocket expenses) received by one co-owner from non-owner, third-party, tenants, is supposed to be shared in proportion to ownership.

Similarly, absent an agreement to the contrary, certain necessary expenses are to be shared in proportion to ownership. These include mortgage principal and interest, property taxes, insurance and necessary maintenance and repairs. Costs of additions and improvements are not shared unless the co-owners have agreed in advance to make the improvements. Agreement can be express or implied from the circumstances.

So, legally, absent some other agreement between you, would be like a little mini-business where the rent comes in, the expenses of doing the rental (additional utility expense, for example) gets reimbursed to the co-owner(s) who pay(s) the bills, and the balance gets divided in proportion to ownership.