Each county or municipality shall be jointly and severally liable for all legal obligations of a fund which arise out of an event which occurred while such county or municipality was a member of such fund; provided, however, that a fund shall not assume a risk greater than an amount to be determined by the Commissioner; and provided, further, that this legal obligation may be enforced by an assessment against such member as provided in the bylaws of the agency.
OCGA § 36-85-9