Central Domestic Hot Water system maintenance

Last year, and with a previous company, I led a study for Southern California Gas Company on the performance of controls that were being installed on CDHW systems in multifamily buildings. We were able to determine that they were getting a lot less energy savings than they expected, but an even bigger issue emerged. Virtually all of the roughly 140 CDHW systems we inspected had maintenance issues. Some minor, some very severe, but mostly moderate; and most systems had multiple issues. Our estimate based on the kinds of issues and the actual billing data (which we had from the Gas Company) was that regular maintenance of the CDHW systems could save about $500/yr per system, at a cost that would less than half that. I am curious to know how many property managers whose properties have CDHW systems, have maintenance contracts with plumbers?
BTW, I can send you a link to the California Public Utilities Commission web site where the report is stored if you are interested - or I can send it directly by email if you'd like. Just let me know.
Thanks,
Nehemiah