Water Meters Freezing

We are doing diligence on a park in Iowa right now that has an interesting water arrangement with the city. The city maintains and reads the individual meters on the tenant owned homes, but holds the park owner responsible for any discrepancies between the master meter reading and the cumulative reading between all sub-meters. This park had 35 of these meters freeze and break last year and thus, caused about $8,000 worth of leaks.
The current owner has been successful in recouping the meter repair costs from the tenants which runs approx. $110 per replacement, but is still coming out of pocket for those leaks via the water bill overages. A problem that we have identified is that many of the meters are not insulated properly (no heat tape or insulated meter box) and all meters are located under the trailer so accessing them is a pain. My questions are has anyone ever instituted a periodic inspection program to ensure the heat tape is functioning properly? What is the best way to keep these meters from freezing? Are there any other solutions we should consider for this problem?