My water (city water) comes into my property at the rear of my property. It enters an open cinder block pit 3'x3'x7'deep. The pipe is suspended about 1/2 way down. There is only an uninsulated steel cover on top of this pit. I am very surprised it has only frozen once (this morning @<10 deg) in the last 10 yrs. Anyone have any experience with these? I will insulate this in the future. Just surprised it doesn't freeze more often!