I've been working mostly with investor-owned utilities up to now and had a decent system for LOAs. Just landed a prospect with Pittsburgh Water and Sewer Authority plus Duquesne Light. Duquesne was no problem — standard LOA, got 24 months of billing in about two weeks. But the water authority? They have no formal process for third-party data requests at all. The customer service rep literally said she'd never seen an LOA before. Anyone dealt with municipal utilities that don't have a third-party authorization process?
Municipal utilities and LOAs — completely different ballgame
Municipals are a whole different world. I work a lot in the Cleveland area and the city water department basically told me the customer has to come in person to request records. No third-party release form exists. What I ended up doing is having the client write a letter on their own letterhead authorizing me by name to receive account information, then I hand-carried it to the billing office. Took three visits but I got the data. The key is to not use the word "audit" — say "billing review" or "account analysis" and they relax a bit.
Similar experience in Louisville with LG&E and Louisville Water. LG&E has a standard TPV form. Louisville Water made us jump through hoops. I finally got the client to call their customer service line while I was sitting right there, put it on speaker, and have the client verbally authorize them to release billing history to me. The rep emailed it that same afternoon. Sometimes the path of least resistance is having the client do the heavy lifting on the call.
With municipals I always recommend getting the client to request their own billing history through a public records or FOIA-type request if the utility stonewalls you. Most municipal utilities are government entities subject to open records laws. The bills belong to the customer anyway, so framing it as "I need copies of my own account history" rather than "my auditor needs access" sometimes works better. Also check if the municipal has an online portal — some smaller ones have surprisingly decent account portals where the client can just download PDF invoices themselves.
Frank's point about municipal utilities being subject to FOIA is gold. I had a situation with Memphis Light Gas & Water where they gave me grief for weeks. Client filed a public records request for their own billing data and had everything within 10 business days. MLGW couldn't refuse because it's a public utility and those records aren't exempt. Changed my whole approach for municipal accounts. Now I always have that card in my back pocket.