Collecting rainwater and dew

Rain and dew can give you water when there's no stream or tap nearby. With a few simple materials you can collect a surprising amount.

Collecting rain

1. Use the widest surface you have. A tarp, poncho, plastic sheet, survival bag or bin bag works well.
2. Make a funnel. Tie the corners to trees or weigh them down so the sheet sags in the middle. Put a small stone in the lowest point and a container underneath, or cut a small hole there above your bottle.
3. Let the first rain run off. It washes away dust, bird droppings and dirt from the surface. Start collecting after a few minutes.
4. Use every container. Pots, bottles, bags, even a hollow lined with plastic. Big leaves can channel water into a container too.
5. Cover the water once collected, to keep out insects, leaves and animals.

A sheet of about 2 metres by 2 metres (6 by 6 feet) in steady rain can collect several litres in an hour.

At home or in a town

A roof and gutter collect lots of water quickly. Disconnect a downpipe or place a bucket under it. Roof water often carries bird droppings, moss and dirt, and some roofing materials can add chemicals, so filter and treat it before drinking.

Collecting dew

Dew forms on clear, still nights and is gone soon after sunrise, so you need to be quick.

1. Before dawn, tie absorbent cloth — a T-shirt, towel or socks — around your lower legs.
2. Walk slowly through long grass or low vegetation.
3. Wring the cloth out into a container when it's soaked, then repeat.

You can also wipe dew off smooth surfaces such as a car roof, tarp or large leaves. Avoid plants you can't identify, and avoid vehicles or surfaces that may have chemicals on them.

Dew collection is slow and gives small amounts, but in dry places it can make a real difference.

Is it safe to drink?

Rain collected directly into a clean container is usually fairly clean, but it can still carry germs or pollution, especially near cities, factories or after it's touched a roof, tarp or plants. Dew picks up whatever is on the cloth and leaves. The safe rule: treat it all. Boil it, use purification tablets, or use a filter.

Keep it clean

• Rinse containers before use.
• Keep collected water covered and in the shade.
• Don't mix treated and untreated water, or use the same cup for both.

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