Your rental income is fully taxable in SC.
You will need to check the CO state website for residency requirements, as well as check the SC state website to see what, if anything, is required to become a non-resident. Do understand however, that at best, you will be filing a part-year resident state return for both states, in the year you move. You will not be filing a non-resident return in either state, in the year you move.
See <a rel="nofollow" target="_blank" href="
https://www.colorado.gov/pacific/sites/default/files/Income6.pdf">https://www.colorado.gov/pacific/s...>
I can't find any guidance really, for terminating residence in SC. But I do know that you are considered a resident until you do things like turn in your SC voter registration card, SC drivers license, and SC issued hunting or fishing licenses, and the like. But I think that's just the tip of that iceberg.
