SRL The Self-Reliance Library
C01.S1.N09

The Self-Reliance Library · Water Security

SOLAR STILL

Solar Water Collection Field Guide

Use sun heat, sealed plastic, and gravity to collect small amounts of clean water.

Core rule: A solar still is a clever backup, not a main water source. It makes small amounts and does not remove all chemicals.

1 Still Cutaway

sun damp soil plants cup plastic weight sealed edge drip

Sun warms damp material. Vapor condenses on the plastic and drips into the cup.

2 Build Shape

shallow pit cup centered cone slope weight over cup

The plastic must slope toward the cup. The drip point needs to sit directly above the cup.

3 Do This / Avoid This

Do this

  • Full sun.
  • Sealed edges.
  • Cup centered.
  • Gentle cone.
  • Clean soil source.

Avoid this

  • Shade.
  • Loose edges.
  • Flat plastic.
  • Off-center drip point.
  • Suspect soil.

4 Honest Limits

low yield
slow process
needs sun
not chemical-safe
treat if unsure

Expect small amounts. Never build over suspect soil or rely on this as your only water plan.

5 Build Steps

  1. Pick sunny safe soil.
  2. Dig shallow pit.
  3. Set cup center.
  4. Add damp plants or soil.
  1. Cover with plastic.
  2. Seal edges.
  3. Weight center.
  4. Wait and collect.