My mom has dementia. I do her taxes. I get her SSA-1099 mailed to me. She lives in a different state. How do I make sure she's taxed in her state and not mine?

[Dgyp]

I used H/R Block for her last year but they charged her $100 and her taxes are so simple!  She has SSA, a tiny pension and a Roth IRA that she w/d from.  She lives in OR but I live in CA and the tax person put her SSA income as CA income I guess because the SSA-1099 has my CA address.  Do I need to change anything with SSA to make sure CA doesn't expect her to file here?

[fanfare]

File her state tax return with the state in which she lives.

You should amend CA state return to get back any state tax paid to CA.

@Dgyp 

[xmasbaby0]

What "tax person" listed your mom as living in CA?   It is important for you to understand that neither CA nor OR tax Social Security benefits.   Those states "might" tax the pension income or the retirement account distributions ---so be careful about those.

[Critter-3]

The mailing address you use on the tax return doesn't dictate which state may tax your income.  So if your address is on her SSA form it doesn't mean she needs to file a return in that state if that is not where she actually lives.