During non-peak times, funds are usually withdrawn on the payment date you specify, assuming your e-filed return has already been accepted (received) by your state agency.
If that date happens to fall on a weekend or federal holiday, the funds are typically withdrawn the next business day.
Due to high e-filing volume it may take a few more days for the debit to process and then it can take your bank another few days to post the debit to your account.
No worries; as long as you filed your return or extension on or before April 17, 2018 and you selected April 17, 2018 (or earlier) as your payment date, you won't get penalized for late payment.
In the meantime, keep an eye on your bank account – if it has been more than 7-10 days since your tax return has been accepted, please contact your State Department of Revenue to verify the scheduled debit date.
How to contact your State Department of Revenue: