California Code, Public Utilities Code - PUC § 779.2

(a) No electrical, gas, heat, telephone, or water corporation may terminate residential service for nonpayment of any delinquent account or other indebtedness owed by the customer or subscriber to any other person or corporation or when the obligation represented by the delinquent account or other indebtedness was incurred with a person or corporation other than the electrical, gas, heat, telephone, or water corporation demanding payment therefor.

(b) Subdivision (a) does not apply to a telephone corporation operating within service areas which furnishes billing services to the subscribers of a telephone corporation operating between service areas pursuant to tariffs on file with the commission providing for the furnishing of those billing services.  The commission shall require that these tariffs also provide for adequate subscriber notice, review, and appeal procedures prior to any termination of service for nonpayment of a delinquent account.

(c) Subdivision (a) does not apply to any privately owned or publicly owned public utility which collects sanitation or sewerage charges for a public agency pursuant to agreement under Section 54346.2 of the Government Code or Section 5472.5 of the Health and Safety Code.