Boiling water for safety.

No, you are only concentrating the heavy metals, neurotoxins and the salt in the water.

You need way more context about what you are trying to eliminate from your water to do it safely.

I’d like to read a survival guide based on actual locations rather than old boy scout tricks.

If you strand on a deserted island in the year 2026 you will find a heap of plastic bottles and other trash that can be made into a solar powered distillery or desalination device. It might still be full of micro plastics but whatever so is the the bottled water in the grocery store.

Actually if you ever get in a survival situation besides falling off a ship, your best option is probably to rob the nearest grocery store. It’s a great resource that can be found in the most desolate places.