Is water/fuel seperator heated?
 

So, with my Duramax, the filter/separator was very close to the engine block, and was essentially heated.

With my 2017 6.7, it is exposed under the truck. I live in the mountains of New Hampshire, and it will probably be below freezing from now until March.

What keeps the separated water, if any, from freezing solid.

Curious minds...

Warm fuel. Gets recycled back from the engine through the separator to keep it “warm” and help prevent fuel gelling.

You can run so anti gel as well.