Legal Question in Real Estate Law in California

Yes, the question is by how much and when. If they have a lease, you cannot raise the rent until the lease is up for renewal. If they are on month-to-month, you must give either 30 days or 60 days notice, depending on the percentage of increase, and the percentage is cumulative over a rolling 12 month period. So unless there has been no rent increase in at least 12 months, calculating the percentage is slightly complicated. It sounds like you are a new landlord if you are having to ask questions like this. I strongly suggest you download and read carefully this document: http://www.dca.ca.gov/publications/landlordbook/catenant.pdf It would also be a good idea to browse the Nolo Press website at nolo.com and pick up some of their publications for landlords.

read their leases. That establishes their terms and conditions. Study and learn the rules and laws for landlords if you want to avoid legal problems, like getting hauled into court for doing things you are not allowed.

You had better be sure that they are not in a rent controlled area. If the property is subject to rent control, there are severe limits on how much you can raise the rent, and when, regardless of the terms of the lease.