California Code, Civil Code - CIV § 1788.15

(a) No debt collector shall collect or attempt to collect a covered debt by means of judicial proceedings when the debt collector knows that service of process, where essential to jurisdiction over the debtor or their property, has not been legally effected.

(b) No debt collector shall collect or attempt to collect a covered debt, other than one reduced to judgment, by means of judicial proceedings in a county other than the county in which the debtor has incurred the covered debt or the county in which the debtor resides at the time those proceedings are instituted, or resided at the time the debt was incurred.

(c) Notwithstanding subdivision (b), when the obligation of the debtor arises from a guaranty by the debtor of a covered commercial debt, a debt collector may collect or attempt to collect covered commercial debt by means of a judicial proceeding in the county in which the nonnatural person for whose purpose the commercial debt was incurred is located.

(d) This section shall apply to all delinquent covered commercial debt sold or assigned on or after July 1, 2025.