"As I stated this Non-Deductible accounts are exclusively used for Non-Deductible contributions... no traditional IRA contributions included." There is no such thing as a "Non-Deductible account". Non-deductible IRA contribution are no different than any other IRA contribution and the IRA non-deductible basis applies to all Traditional IRA account in aggregate.
You can NEVER withdraw ONLY the nondeductible part - it must be prorated over the entire value of ALL Traditional IRA accounts which include SEP and SIMPLE IRA's. (For tax purposes you only have ONE Traditional IRA which can be split between as many different accounts as you want, but for tax purposes they are all added together).
For example using rough figures: if you had $60K of nondeductible contributions in an IRA with a total value of $600K (10:1 ratio), then when you take a $60K distribution from any IRA account $6,000 would be nontaxable and $54,000 would be taxable (same 10:1 ratio) , with the remaining $54K of basis staying in the IRA for future distributions. As long as there is any money in the IRA, there will be some basis.
TurboTax will ask for your non-deductible "basis" and then the *Total Value* of *all* Traditional IRA, SEP and SIMPLE accounts as of Dec 31, of the tax year. That is so the prorating of the basis can be properly proportioned between the current years distribution and the remaining IRA value. That is done on the 8606 form.
This so-called “back-door Roth” method ONLY works if you have NO OTHER Traditional IRA accounts. If you do, then the non-deductible part must be spread over ALL accounts and cannot be withdrawn by itself. Only if you started with NO Traditional, SEP & SIMPLE IRA and ended up with a zero amount in ALL Traditional, SEP & SIMPLE IRA accounts will this Roth conversion not be taxable.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
