What keeps watermains from freezing and bursting in winter?

Moving water doesn’t freeze!!! On our coldest nights, we turn our water on to a trickle & even without the heat, the water doesn’t freeze. My Gramps had a pond on his farm & he ran hoses from the pond, down the hill to use for watering his animals. As long as the water was flowing down hill, it did NOT freeze!!

They’re below the frost line too. The ground is naturally warm at depth so it never gets below freezing because they intentionally bury the water and sewer lines at a depth that will never freeze. Also, @LadyMarissa is correct that moving water never freezes.

So we have that the water mains are underground and that the water moves more which both contribute to them not freezing. Additionally the piping is thicker than what you have in a house. this means the piping walls are thicker and harder to split and the water inside is a larger volume…kinda hard to freeze it solid with the flow inside.

I read the Q as watermelons, wow. Ha!

^^ I can see that happening! :D

The average temperature of the ground below the frost line is around 40* F to 55* F, even in the winter.

Moving water can freeze, according to these Pictures of Niagra falls

@Tropical_Willie yes, I went in one of these caves, sort of like Luray Caverns, and they explained to us that once we got inside, the temperature never varied past somewhere around 55 or 60°. Of course, if you went down deeper, it would get hotter.

Water lines that are exposed to weather are usually heat taped and insulated so they do not freeze.

Sometimes they do

@KNOWITALL Now, you have me wanting some watermelon! We’re halfway through August, and summertime delights won’t be here forever.

They are buried below the frost level, usually 4 feet.