Legal Question in Real Estate Law in California

Laws about rent control vary from municipality to municipality, but in general, lack of a written agreement won't affect a tenant's rights under local laws, or under state law, insofar as rent increases are concerned.

Separately, I'd add that oral rental agreements are enforceable by either party provided the term of the oral agreement does not exceed one year; longer agreements need to be in writing and signed.

So, I'd say yes, but only as permitted under written agreements in the same rent-control jurisdiction. You as a landlord gain nothing in terms of rent flexibility by not having your rental agreement in writing.

It depends on whether or not the property is subject to rent control, and it also depends on the amount of the rent increase and the amount of notice you give. It is my understanding that portions of San Diego now have rent control. The amount of notice you give to raise rent also depends on the percentage of the rent increase. See Civil Code section 827, specifically subsection (b).