When does the IRS take payment for federal taxes if I opted to pay through Turbotax?

I filed my taxes in early march, a month ago, and owed some federal taxes. I opted for bank draft to pay up, but the money still hasn't been withdrawn. I know I put in the correct bank info because my state return came back just fine. Does the IRS collect when taxes are due or is this something I need to pursue to make sure it's paid?