[edited] If you were a Cailfornia resident when you received the proceeds of the sale, the entire amount is taxable by California. CA residents are taxed on all income, regardless of its source.
https://www.ftb.ca.gov/forms/2021/2021-1031-publication.pdf
If you were a Washington resident when you received the proceeds of the sale, your capital gain is not subject to California tax. Nor would you have any tax due to Washington, since Washington does not tax capital gains from the sale of real estate.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
