Legal Question in Wills and Trusts in California

I am sorry for the loss of your mother. As I understand it, you are assuming the duties of successor trustee because of your mother's death and your father's incapacity. Your residence does not alter the fact that your father's residence is in California or that his trust is a California trust. This is true even though your address will be the location for administration of the trust. I'm not sure what you mean by the taxation of trust accounts. If the trust owes California income taxes, then those taxes would need to be paid to the California Franchise Tax Board. Any income earned by your father (from pensions, social security etc.) would be subject to taxes in California because he is a resident of the state. You should talk to a tax professional because, depending on his income, your father and/or the trust may not owe any such taxes. Property taxes need to be paid to the county in which the trust's real property is located in.