Challenge 103: Construct a Rainwater Collection System Beside a Temporary Camp Using a Tarp and Clean Container

Collecting rainwater can be a useful outdoor skill when you’re staying at a temporary camp. A simple system using a tarp and a clean container can direct rainfall into one place, helping you gather water without relying entirely on bottles or other supplies you’ve brought with you.

The key is to set up the collector so water runs towards the container without spilling, while keeping the collection surface and stored water as clean as possible. For this challenge, you’ll construct a basic rainwater collection system beside a temporary camp and assess how effectively it works.

Your Challenge

Construct a rainwater collection system beside a temporary camp using a tarp and a clean container.

You must demonstrate that you can:

• Position a tarp to direct rainwater towards a collection point.
• Secure the tarp so it remains stable in suitable weather.
• Position a clean container to catch the runoff.
• Reduce contamination from the ground, surrounding vegetation and dirty equipment.
• Inspect the system and explain the limitations of collected rainwater.

You do not need to wait for rainfall to complete the challenge. You can test the arrangement using a small amount of clean water poured over the tarp, then explain how you would maintain the system during a period of rain.

Important: Rainwater collected from a tarp is not automatically safe to drink. For drinking, cooking or brushing your teeth, treat the water using an appropriate method and follow relevant water-safety guidance.

What You’ll Need

• A tarp that is clean and suitable for collecting water.
• A clean container with enough capacity to collect runoff.
• Suitable cordage and secure attachment points.
• A stable temporary camp location.
• A small amount of clean water for testing the system if rain is not available.
• A camera or phone to photograph the finished setup.

Choose a container intended for holding drinking water if you may later use the collected water for that purpose. Do not use a container that has held fuel, chemicals or other hazardous substances.

Inspect the tarp before use. A tarp that has been lying on dirty ground or used for carrying equipment may introduce contamination. Clean it appropriately before setting up the collector.

Take the Challenge

1. Choose a suitable location beside camp

Select a location close enough to your temporary camp for convenient access, but far enough away to avoid collecting runoff from the cooking area, washing area, toilet area or other sources of contamination.

Look for a relatively level area where the container can stand securely without tipping. The tarp needs a suitable position above or beside the container, with enough clearance to direct water into it.

Avoid locations beneath overhanging branches where bird droppings, leaves or other debris could contaminate the collection surface. Consider the direction of the wind and whether it could blow the tarp loose or introduce debris.

Do not position the collector where it could obstruct a path, create a trip hazard or collect water running across the ground. The aim is to capture rain falling onto the tarp rather than scoop up surface runoff.

2. Inspect and prepare the tarp

Check both sides of the tarp for mud, leaves, animal droppings and other contamination. Use a clean tarp whenever possible, and clean it with a suitable method if necessary.

Avoid using a tarp that has been exposed to fuel, pesticides, cleaning chemicals or other substances that could contaminate the water. If you cannot establish that the surface is suitable, use another tarp.

Spread the tarp out and identify the direction in which you want water to flow. A simple arrangement is to create a sloping surface with one lower corner positioned above the collection container.

The tarp should be taut enough to prevent unwanted sagging, but it must still have a clear slope that directs water towards the intended collection point. A deep depression may trap water rather than drain it.

3. Set up the tarp at a suitable angle

Secure the tarp using suitable cordage and reliable attachment points. You might use a simple sloping pitch between supports or another arrangement that creates a clear route for water to drain.

Position the high side of the tarp above the intended drainage point, allowing gravity to carry water towards the lower edge or corner. Check the shape of the tarp from several angles to identify any low spots where water might pool.

Make small adjustments to the attachment points until the surface slopes consistently towards the collection area. Do not climb onto the tarp or use unstable supports to reach a higher attachment point.

Make sure the tarp is not pitched where it could collapse onto your sleeping area or cooking equipment. Avoid damaging living trees when attaching cordage, and follow any site restrictions.

4. Position the clean collection container

Place the container beneath the lowest drainage point so that runoff enters it directly.

Keep the container off dirty ground if you can do so safely, using a clean, stable surface. If it must sit on the ground, choose a firm area away from mud, standing water and potential sources of contamination.

Adjust the tarp so the water falls into the container rather than running down its outside. A small misalignment can waste a surprising amount of collected water, particularly in light rain.

Keep the container open only as needed to collect water. Once collection is complete, cover it with a clean lid or suitable cover to protect it from insects, leaves and other debris.

5. Test the water flow

If it is not raining, use a small amount of clean water to test your system.

Pour the water gently onto the upper part of the tarp, away from the container, and observe how it travels across the surface. It should follow the slope towards the collection point without becoming trapped in a depression or spilling over the sides.

Watch the final section of the route closely. Water may travel towards the intended corner but miss the container if the tarp edge is poorly positioned or the drainage point is too far away.

If water pools, adjust the pitch or tension. If it spills outside the container, reposition the container or change the angle of the tarp.

Repeat the test until the water follows a clear route into the container. Empty the test water afterwards if you cannot be certain that the system remained clean during the test.

6. Check for contamination risks

Inspect the entire system, not just the container.

Check whether the tarp could collect debris, whether the collection point is exposed to splashes from the ground, and whether the container could be contaminated by dirty hands or equipment.

Keep the collection area separate from washing and cooking activities. Do not allow ropes, boots or other dirty equipment to come into contact with the inside of the container.

Rainwater may contain microorganisms and contaminants from the atmosphere or the collection surface. Even clear water with no noticeable smell may be unsafe to drink.

If you intend to use collected rainwater for drinking, use an appropriate treatment method suitable for the possible contaminants. Boiling can kill many disease-causing microorganisms, but it does not remove chemical contamination. If chemical contamination is suspected, do not drink the water.

7. Assess the system’s stability

Walk around the setup and check that the tarp, cordage, supports and container are stable.

Consider what might happen during stronger rain or gusty weather. A container may fill and become heavier, while wind can loosen attachment points or cause water to miss the collection point.

Do not leave the system unattended in conditions that could make it unsafe. If the weather deteriorates, dismantle or lower the tarp if you can do so safely.

Check that overflow will drain away from your sleeping area and will not create muddy ground or a slippery route through camp.

Once you are satisfied with the arrangement, take a photograph showing the full system and its position beside the temporary camp.

Check Your Results

You have completed the challenge when you can demonstrate that:

• You selected a suitable location beside your temporary camp.
• You inspected and prepared a clean tarp.
• You pitched the tarp so gravity directs water towards a collection point.
• You positioned a clean container to catch the runoff.
• You tested the water flow and corrected any pooling or spillage.
• You considered contamination risks and how to protect the collected water.
• You checked the stability of the system and considered how it would behave in rain and wind.

If water cannot reach the container reliably, adjust the pitch before claiming success. A good system should collect water deliberately rather than depend on rainfall happening to fall in the right place.

Complete the Challenge

Construct your rainwater collector and test that water can flow from the tarp into the clean container.

Take a clear photograph showing the tarp, its support points, the drainage point and the container. Include enough of the surrounding camp to demonstrate that you positioned the system thoughtfully.

In your written submission, explain how you created the slope, how you checked the water flow and what you did to minimise contamination. State how you would treat the water before drinking it.

You can complete this challenge without rain by testing the setup with a small amount of clean water.

How to Submit Your Challenge

1. Log in to your Pure Bushcraft account.
2. Visit your member profile and open the Social Activity section.
3. Create a post containing a photograph of your completed rainwater collection system.
4. Include the hashtag #PureBushcraftChallenge103.
5. Briefly explain how the system directs water into the container and how you would keep the collected water safe to handle and use.

Your submission will be checked before the challenge is marked as verified.

Challenge 103 Checklist

Want to Push Yourself?

Once your basic collector works, experiment with two different tarp pitches and compare how effectively each directs water into the container.

Try adjusting the slope or changing the position of the collection point while keeping the rest of the setup as similar as possible. Observe where water travels, whether it pools and how much reaches the container during a controlled test.

You can also calculate how much rainwater a tarp could theoretically collect. Multiply the rainfall depth in millimetres by the tarp’s effective collection area in square metres to estimate the volume in litres, before allowing for losses from wind, splashing and runoff.

For example, 10 mm of rain falling onto a collection area of 2 square metres represents a theoretical 20 litres of water. The actual amount collected will usually be lower.

What’s Next?

Continue developing your outdoor skills by revisiting Pure Bushcraft Outdoor Skills Challenge 102: Prepare a Fire Lay Using Only Responsibly Gathered Deadwood if you haven’t completed it yet. That challenge focuses on selecting and arranging natural fire materials responsibly.

The Pure Bushcraft Challenges can be completed in any order. Keep practising practical skills that help you manage your temporary camp efficiently while protecting the surrounding environment.

Once you’ve shared your evidence and it has been verified, the Pure Bushcraft Outdoor Skills Challenge 103 is complete and the completed challenges figure will be updated on your profile.