Remember back in the day when you wrote a check and you could count on at least a few days before it was cleared by your bank?

That “float” bought you some time for a check you deposited to cover the one you’d already written to clear. Or gave you a chance to run and deposit cash into your account.

Well, the float is mostly being washed away. Beginning Friday, merchants will be able to take advantage of a new way to electronically clear checks. It’s called “back office conversion,” or BOC.

This process allows retailers and businesses that accept consumer and business checks of less than $25,000 to clear them through the ACH network, which is the same network used for payroll direct-deposit transactions. The checks are then converted from paper to an electronic debit later at a centralized location.

This process isn’t as immediate as a debit transaction, but if you write a check during the day, you can count on it clearing the following business day.

Merchants are required to disclose to customers that their checks will be converted into an electronic payment, according to rules established by NACHA, the nonprofit Electronic Payments Association that develops business practices for electronic payments. The notice has to be prominently displayed at the register and on a customer’s receipt.

Other businesses to whom you pay bills with a check must provide this written notification of the back office conversion on the billing statement or on a separate enclosure with the bill you receive in the mail.

You can opt out of having your check electronically converted in a back office process, says Elliott C. McEntee, president and CEO of NACHA. Having your check converted through a BOC has another advantage, McEntee adds. Because the transaction is being electronically processed, it is covered under the Federal Reserve’s Regulation E, which provides extra consumer protections for electronic fund transfers, such as a longer time to report an error. Additionally McEntee notes that under NACHA rules, if there is an error or unauthorized debit from your bank account, the financial institution has to immediately credit the money back to you while an investigation is conducted.

For retailers, there are big savings to be had with back office conversion, says Danne Buchanan, chief executive of NetDeposit. Retailers don’t have to physically take the checks to the bank, and accelerated processing results in fewer bad checks, according to Buchanan.

McEntee points out that many merchants may decide to test back office conversion before implementing it throughout their stores.

Still, let this be your notice. For the most part you no longer have a check-clearing cushion. The various ways businesses are clearing checks mean that when you write a check, you better have the money in your account.