"Registering an address," whatever that means, has no effect on whether you are a resident of a particular state. And "saying" you are a resident somewhere doesn't make you a resident. Here is a link to the California FTB publication that describes what determines whether you are a California resident for income tax purposes.
FTB Publication 1031, Guidelines for Determining Resident Status
One of the things that is discussed in the publication is the concept of domicile, which is different from residence. In most cases, if your domicile is in California you will be considered a California resident, even if you spend very little time there during the year. Also note that, since every state has a different definition of a resident, it is possible to be considered a resident of more than one state at the same time. So being a Washington resident would not necessarily mean that you are not a California resident. You can have only one domicile, but you can have multiple residencies.
The California Franchise Tax Board (FTB) is very aggressive about collecting taxes. If your situation is unclear, they will probably say you are a resident, unless you can prove otherwise. "Living in my family home outside of Los Angeles" strongly suggests that the family home is your domicile.
And again, if you do any work in California, even for a short time, you have to pay California tax on that income, even if you don't live there and are not a resident.
A "nomadic lifestyle" does create complications in determining where you have to pay taxes. You might have to pay tax in several states. It might be a good idea to consult a tax professional to advise you on how to handle your situation.
