Cal. Gov. Code § 31009
Prior to January 1, 1981, an applicant for employment who does not meet the physical standards established for his employment because of a physical impairment existing on the date of his employment may be required by the county as a condition to such employment to execute a waiver of any and all rights to a disability retirement under the County Employees Retirement Law of 1937 arising as a result of such impairment or any aggravation thereof while in county service. The county shall provide the applicant with written notice of the rights and benefits which such applicant is being required to waive. The applicant shall give written acknowledgement of the receipt of such notice.
No earlier than two years after employment an employee who has waived rights pursuant to this section may apply to the retirement board to review such waiver to determine if it shall remain in force. The employee shall submit a physician's report concerning the condition for which such a waiver was required with such request for review. The retirement board may require, at county expense, an examination of such employee by a physician of such board's choosing. The retirement board, following a hearing, may release such employee from all or part of a waiver given pursuant to this section. An employee may not require such a review more often than every two years, although such board in its sole discretion may allow a review at more frequent intervals.
Ca. Gov. Code § 31009