My gas and electricity utility company has not billed me for any of my use since I moved in to my apartment 6 months ago. To this day, I still have not gotten a bill. If they decide to bill me in the future for all of the past months that I have not been billed, am I legally obligated to pay? How long can they go without billing me before I don't have to pay their eventual bill if any? I am in California and the utility company is a public utility company called SDG&E.