There are two issues relating to rent increases: legal and market. Legalling, you should be able to raise the rent by up to 10% on an annual lease, unless the tenant is 65 years or older, then it's 5%. Regarding the market, professional managers usually do a market rent analysis to see if rents should be raised, lowered, or stay the same. Everyone has a different process, but a simple approach is to define your market geographically, pick out rental properties that are comparable to yours in that market and create a side-by-side comparison on a spreadsheet. San Diego contains 30+ housing "markets", so you should be careful not to compare a house in Rancho Penasquitos with a house in Bird Rock. Also, compare your house to other houses of the same size and ammenities (eg swimming pool, 2 car garage, etc.), don't compare it to an apartment. I hope this helps.