It depends but you will need to report the sale on your federal and CA resident state income tax return whether or not you have a capital gain or loss on this rental property. Since WA has no individual state income taxes, you will not have any income tax filing requirements in WA.
You will need to include this on your CA resident state income tax return because, as a resident of CA, you are taxed on all income from all sources (including any gain (or loss) for the sale of a capital asset located in another state).
One additional note -
When you sell a
property that was used as a rental, you must pay 25 percent recapture tax (also
referred to as Section 1250 recapture) as well as regular state income tax on
the depreciation you claimed. (Remember the IRS will assume that you claimed
the correct amount of depreciation every year—this is true regardless of
whether you actually claimed any depreciation on your tax return). The gain on the recapture will be taxable on both your federal and resident state income tax returns. (Unfortunately, California taxes both capital gains and recapture as regular income.)
