Why don't water towers freeze solid in the winter?

What keeps water towers from freezing? - Quora

Ice Calculations and Safety - Grit

Water tower water tower frozen by the cold hi-res stock

4 Low-Tech Ways to Fight Frozen Water Troughs

Engineering, HowStuffWorks

How to Keep Your Well Water System From Freezing in the Winter

Why don't water towers freeze solid in the winter?

How to Prevent a Water Tank from Freezing in Winter

Glaciers: Moving Rivers of Ice

Frozen Water Tower on Route D - Boone Country Connection

Structural Engineering, HowStuffWorks

Here's what you need to know about those icicles on your home