I believe that only requirement to form a state is to have 60,000 residents. There is actually a clause in the Texas State Constitution reserving the future right to break into four separate states if ever desired. I'm surprised the more conservative parts of California haven't tried this already.
California did think about it about 15 years back. One of the issues concerns sending Northern water to Southern CA to wash their cars, while the North are put on water restrictions along with the farmers, and salt water intrusion fills the fertile valley.
Pima: A reason to seek secession is when people pay taxes and then watch them all go to the rich areas of the state, while their poor areas suffer. Or when they have issues that their state will refuse to address, like the Southern border and need for policing and protection.