Distributions from a Roth 401(k) are prorated between nontaxable amounts (your original Roth contributions) and taxable amounts (earnings). The law requires that the payer withhold a minimum of 20% of the taxable portion of the distribution for federal taxes. Presumably you are under age 59½, so the distribution is subject to a 10% early-distribution penalty on the taxable portion of the distribution.
You would likely do better to roll some or all of the Roth 401(k) over to a Roth IRA and then take distributions from the Roth IRA. Doing so would result in your Roth 401(k) contribution basis becoming contribution basis in the Roth IRA. Under Roth IRA ordering rules distributions are not prorated between taxable and nontaxable amounts but, instead, your contribution basis is distributed first, tax and penalty free. It won't be until you dip into the earnings that you will begin to distribute from the Roth IRA portions that are subject to tax and penalty.
To avoid the 20% mandatory withholding on the movement of the Roth 401(k) to the Roth IRA, the movement must be done by direct rollover, with the plan making the distribution payable to the Roth IRA for your benefit. If you don't already have a Roth IRA account you'll need to establish the account to receive the direct rollover, then provide the information to the 401(k) plan administrator so that they can make the payment to that account.
Virginia taxes Roth IRA distributions the same way, so, again, you'll benefit from rolling the Roth 401(k) over to a Roth IRA first.
The 401(k) plan may have restrictions on the frequency of distributions. If so, you'll want to take that into account in determining the amount to roll over to the Roth IRA. Whatever amount you do roll over, you'll want to make sure that the portion of the distribution from the Roth 401(k) that is nontaxable is large enough to meet your needs when later distributed from the Roth IRA.
