FeatherSticks · Water
How to Collect Rainwater When Camping (and Dew, Honestly)
One millimetre of rain on one square metre is one litre. Catch it.
Quick facts
- Rule of thumb
- 1 mm rain × 1 m² = 1 litre
- Difficulty
- Easy — a tarp, a cord, a pot
- Best for
- Rainy camps, ridges and dry forests
- Still needed
- Treat: boil, filter or disinfect
What you need
- Tarp or poncho with corner tie-outs
- Cord: guylines plus about 50 cm for the drip line
- Pot with lid, or a folding bucket
- Wide-mouth bottles or a water bag kept only for water
- Clean cotton cloth or bandana for pre-filtering and dew
- Water filter or purification tablets, and a stove for boiling
Step by step
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1 Pitch in the open, one corner low
Set the tarp up taut under open sky, not under dripping trees, and drop one corner so the whole sheet drains to a single point.
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2 Let the first rain rinse the tarp
Let the first 5–10 minutes of steady rain run off onto the ground. It carries away dust, pollen, needles and bird droppings.
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3 Lead the water into the pot
Tie a short drip cord to the low tie-out and hang its weighted end in a clean pot, so the water follows the cord instead of blowing past.
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4 Decant into clean, closed bottles
Pour through a clean cloth into bottles you keep only for water, close them and store them in the shade. Swap pots before they overflow.
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5 Treat it before you drink
Cleanly caught rain is low-risk but not guaranteed clean. Hold a rolling boil for 1 minute, 3 minutes above 2,000 m, or filter and disinfect.
Common mistakes
- Counting on rain instead of carrying or mapping reliable water.
- Collecting under trees and getting brown canopy drip full of debris.
- Catching the first run-off with all the dust and droppings from the tarp.
- No clear low point — the tarp drips from every edge except over the pot.
- Letting water pool in a slack shelter tarp until a tie-out rips.
- Using the unwashed dinner pot and then storing the water for days.
- Drinking it untreated because rain "is clean anyway".