by Ken Golliher: My understanding is that any requirement that "pre-notes" be sent was removed from the NACHA rules several years ago. Even when they were required, there was nothing in particular the RDFI was required to do with them.
by John Burnett: NACHA rules Section 3.5 indicates that an RDFI is responsible for verifying that the account number contained in a received Prenotification is for a valid account. If it does not contain a valid account number, the RDFI is required to send either a Return Entry or a Notification of Change. The point of the "Prenote" isn't necessarily to notify the Receiver (your customer) of the impending ACH access (it's presumed he or she knows). Instead, it's to ensure that the Originator has valid account information.
The "flip side" of the Prenote is the responsibility of the ODFI to get its Originator to make needed changes before sending "live" debits and credits.
Based on my observations, the Prenote process, which the Originator is not required to use, is often overlooked, and when it is used, it's often not used correctly.