CA Health & Safety Code Section 127440

The hospital shall reimburse the patient or patients any amount actually paid in excess of the amount due under this article, including interest. Interest owed by the hospital to the patient shall accrue at the rate set forth in Section 685.010 of the Code of Civil Procedure, beginning on the date payment by the patient is received by the hospital. However, a hospital is not required to reimburse the patient or pay interest if the amount due is less than five dollars ($5.00). The hospital shall give the patient a credit for the amount due for at least 60 days from the date the amount is due.