Cal. Ed. Code § 1294.5
Any county superintendent of schools may employ persons possessing an appropriate credential as certificated employees in programs and projects to perform services conducted under contract with public or private agencies, or other categorically funded projects of indeterminate duration. The terms and conditions under which such persons are employed shall be mutually agreed upon by the employee and the county superintendent and such agreement shall be reduced to writing. Service pursuant to this section shall not be included in computing the service required as a prerequisite to attainment of, or eligibility to, classification as a permanent employee unless (1) such person has served pursuant to this section for at least 75 percent of the number of days the regular schools of county superintendent by which he is employed are maintained, and (2) such person is subsequently employed as a probationary employee in a position requiring certification qualifications. Such persons may be employed for periods which are less than a full school year and may be terminated at the expiration of the contract or specially funded project without regard to other requirements of this code respecting the termination of probationary or permanent employees.
This section shall not be construed to apply to any regularly credentialed employee who has been employed in the regular educational programs of the county superintendent of schools as a probationary employee before being subsequently assigned to any one of these programs.
Ca. Educ. Code § 1294.5