I know there is a number of postings on the general topic, but trying to go a different direction here.
My park is in the midwest and every winter we lose a few meters or at least the freeze plates to the cold.
Trying to think of something that takes the human element out of it, as people are lazy and unreliable (including myself BTW!).
Like heat tape tied directly into a breaker box that comes on when the temp drops below a certain level and keeps the lines/meters from freezing.
i.e. requirements are something the comes on automatically to prevent pipes/meter from being damaged. Tenant doesn’t have to remember to plug something in or open the faucet slightly. But doesn’t run all year long wasting electricity.
I talked with a plumber and he said that he would recommend on a new setup , running the meters into the home where they are stored there. Kind of an impractical cost/ solution and probably still will carry some risk but just throwing it out there
You might want to consider using “self regulating heating cable” or “Pipe Heating Trace Cable”. Widely used in the livestock industry up here in cold country, it puts out more heat as the cable gets colder and less as it gets warmer so you could just leave it plugged in 365. Can be wrapped over itself without melting the cable You can buy it in bulk rolls and add plug end to make custom cable lengths. I saw quite a few options over at [More Electric Heating ][www.morelectricheating.com].