Oh man, what a crazy hassle! Suggest you take a close look at the meter and pipes, see if there are any seals that would help prove PG&E did the work (such as wires with lumps of metal glommed on). That they have read the meter all these years and accepted payment would seem to establish that there was nothing amiss, but you may need the services of a lawyer to explain that in the correct language, and to the correct people within the company to get them to back off. Good luck, and stay away from the liquor cabinet in the meantime ;-)
Couple, three years or so ago, PG&E came around and installed "Smart Meter" cellular reading attachments to all their meters, both of these included. Both of them have anti-tamper seals on them, the last time I looked at them. PG&E knows these are legitimate maters. They found BOTH accounts. . . I am just talking with dodos. It's the gas LINE they are claiming is somehow "unauthorized" that they hooked their meter to. How they get that idea I have an inkling of a clue.
The leak was called in to the front address due to both meters being attached to the front house. It's address number is 656. The back house is 654. . . the technician comes out to 656 finds a leak and traces a pipe that now has a leak but it goes from the meter for 654 and then to 654. 656 has no record of an authorized pipe for another building going toward the back! Voilá! Unauthorized gas piping! RED TAG! Technician thinks the second meter is for an apartment in 656 and extra pipe is unathorized, unpermitted later additional work to send gas to back buildings because it's not on the record for 656!
However, when the back house was built, the address it was built under and permitted was 654, all gas plumbing was authorized under 654, all records are under 654.
The city has told me it is odd, since the lot was never subdivided, that the address on the second house was not 656½ which is the normal way of handling it. But my parent's lot was an oversize lot (65' wide but 265' deep — we kids called it "the 'way back," which meant "way back beyond the incinerator," because the incinerator was right next to a fence that split the backyard in to two backyards— but a smidgeon too small to permit subdividing, so the city clerk issued a full address back in 1953 when my dad pulled a permit to build. By-the-way, the neighbors to the north of us had an even longer yard, maybe another 20' longer, but everyone else on our block had much shorter yards which were equal to the ones of the houses on the next block. The neighbors behind just the two middle lots on our block facing the other street had tiny backyards because the guy who owned the farm land in the 1930s lived on that piece and then finally subdivided it to make those two big lots for friends who wanted big gardens after developing the rest into equal sized lots.)
Having an unsubivided lot with two houses has caused a bunch of problems for me because other utility companies don't know how to do multiple dwelling billing. For example, the water company will not split the water and garbage bill for my two tenants, even though there are two water meters and two garbage services. They insist It's only one lot, so only one bill because their software uses the city's plot number as an account number. AAARRRGGGHHH!
Senseless. Ain't it?
What do they do for a high-rise condominium on one plot? I asked them. They bill the association, who has to bill each owner for their water use, and they are forced to have a joint garbage system.