The water meter box that connects to the county water district is concrete. It has a metal flap on top. The metal flap has a tiny vent about 1/2" x 1" in size. When it gets wicked cold in the winter temperatures typically drop to 20F. I'm wondering what is the need for the air vent? Why does the water district not worry about freeze damage to the valves that are exposed to air through the vent? The valves are metal, possibly brass. Water pipes need to be buried 18 inches to avoid freeze damage but the main valve is exposed to cold air outright.
I suspect that when the valves freeze they end up leaking not breaking. A leaking valve will harm the customer but not the water district. So the water district doesn't care.