Does Durable POA in California need to be filed with the state to be legal?

In Texas - DEFINATELY!

I think it depends on how the POA is written and the if you have a conservatorship. I live in California and my mother's DPOA is written as a springing DPOA. We could not use the DPOA until my mother was certified as mentally incapacitated. Once we got a letter from a neurologist stating my mom could no longer make decisions for herself due to Alzheimer's Disease, we took that letter to mom's attorney and he accepted it. Since my sister is named as the trustee on mom's accounts, mom's attorney filed with the courts making that change. We do however, have to present a copy of the neurologists letter along with the DPOA. We have only run into PG&E giving us some problems.

No it does not. It only has to be notarized. I had to have it for my MIL. Everyone excepted it, however, her bank wanted to go one step further, and made me do one for them, using the one I had.

I had poa in cal and unless the attorney filed for me I never did