What is the max time for a residential lease agreement in CA?

[Mike Chen]

We have a property in California (Santa Clara County) that we are going to be leasing out to family at below market value (permanent resident instead of investment home). What is the maximum time period we can assign this? We have heard:

-That while there is no lease limit to commercial properties, a maximum lease limit for residential in three years in California. 

-That contract parameters are up to landlord discretion as long as tenant agrees to it, even if it says "renews in perpetuity until mutual dissolution" 

-That there is no maximum cap in California but you can only set years, not open ended. 

So basically three different answers, three different sources. I tried looking at the state website for landlord guidelines but couldn't find anything about this specific question. Any insight? Regadless, we will have a lawyer draft the contract but as they are expensive on an hourly basis, we'd like to go in with an educated POV first. Thanks!