Send Form 592V with a check or money order when you submit the nonresident or backup withholding amount on California source payments to us. If you have any doubt about the requirement to withhold, go ahead and do it and use a Form 1042.Gov and search for withholding requirements for updates, online tools, and more information, including: Forms and Publications What are the withholding rates for foreign. (non-U. According to the Migration Policy Institute (MPI ), about 800,000 Canadians are residing in the United States.