In general, savings accounts are not covered by Reg CC timeframes unless, a) your state law requires that they are or b) You have inlcluded savings accounts in your funds availability policy and disclosures.
If neither a nor b apply, you can put whatever hold you would like on a savings account.
Repeat overdrafts are defined in the regulation.
(d) Repeated overdrafts. If any account or combination of accounts of a depositary bank's customer has been repeatedly overdrawn, then for a period of six months after the last such overdraft, Secs. 229.10(c) and 229.12 do not apply to any of the accounts. A depositary bank may consider a customer's account to be repeatedly overdrawn if--
(1) On six or more banking days within the preceding six months, the account balance is negative, or the account balance would have become negative if checks or other charges to the account had been paid; or
(2) On two or more banking days within the preceding six months, the account balance is negative, or the account balance would have become negative, in the amount of $5,000 or more, if checks or other charges to the account had been paid.
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