CA Fam Code Section 4202

(a)

Notwithstanding any other provision of law, in a proceeding where the custodial parent resides in one county and the parent ordered to pay support resides in another county, the court may direct payment to be made to the county officer designated by the court for those purposes in the county of residence of the custodial parent, and may direct the local child support agency of either county to enforce the order.

(b)

If the court directs the local child support agency of the county of residence of the noncustodial parent to enforce the order, the expenses of the local child support agency with respect to the enforcement is a charge upon the county of residence of the noncustodial parent.