SKILL 72: How to Build a Solar Still
Water doesn’t vanish when the land looks dead.
It sinks.
It hides.
It waits below the surface where heat can pull it back out.
A solar still isn’t clever.
It’s patient engineering that lets the environment do the work while you conserve energy and avoid mistakes.
What It Does
• Extracts drinkable water from soil, plants, or even saltwater
• Works without fire, fuel, or moving parts
• Produces clean condensation while you focus on shelter or signaling
• Buys time when searching costs more water than it returns
This is not fast hydration.
This is how you stay alive when nothing obvious is left.
The Core Rule
Heat does the lifting.
Plastic does the trapping.
Gravity finishes the job.
Break that chain and the still becomes a hole in the ground.
Solar Still Basics (Field Method)
1. Choose ground that wants to give you water
Dry-looking ground can still hold moisture, but some places work harder for you than others.
Look for areas where life tried to grow — green plants, low terrain, dry streambeds, or damp sand that cools slowly after sunset.
The richer the ground, the less effort the sun needs to extract moisture.
2. Dig for depth, not comfort
A shallow pit looks easier and fails quietly.
Go 2–3 feet deep, shape it like a bowl, and smooth the walls so collapsing dirt doesn’t steal your output.
Depth is what creates temperature difference.
Temperature difference is what creates water.
3. Set the collection cup like it matters
Place it dead center, stable, and clean.
Every drop you get is aiming for this point.
Miss it, and the whole system wastes effort.
4. Stack the odds with extra moisture
You don’t have to rely on soil alone.
Green leaves, damp cloth, even urine can be added around the cup — never inside it.
Evaporation doesn’t care where the water came from.
Only that it’s there.
5. Seal the system completely
Use clear plastic, pulled tight and locked down with dirt or rocks.
No gaps.
No slack.
Every leak is water escaping before it ever becomes useful.
6. Create a deliberate drip point
Place a small stone directly over the cup so the plastic slopes inward.
Condensation needs guidance.
Without slope, water clings and evaporates again instead of collecting.
7. Walk away and let time work
This is not something you hover over.
Sun heats.
Moisture rises.
Condensation forms.
Drops fall.
Check in the afternoon when production peaks, and adjust only if something failed.
Tips
• Multiple small stills outperform one large one
• Plastic stretches — re-tighten as needed
• Output is slow but consistent
• Only drink what condenses, never raw pit water
Bottom Line
A solar still won’t save you in an hour.
It saves you by not making things worse, by giving you steady water while your energy stays intact.
Dig with intention.
Seal with care.
Let patience do the work.
Water rewards discipline.
