How To Collect Rainwater Without Gutters Or A Roof | Build a Stash

You need to capture rainwater but don’t have to use the water runoff from your house. Let’s explore how to collect rainwater without gutters or a roof.

Catching rainwater without using gutters or from a rooftop is easier than you might imagine. You need a container or (a tarp strung up and angled toward a container also works). For larger applications, you can dig a hole in the ground, line it with polystyrene and have it collect rainwater.

Many survivalists, outdoors people, and even planters of roof gardens know the value of rainwater harvesting. They learn that water isn’t just crucial for bringing May flowers (April showers). It can be critical for the survival of both humans and vegetables. Whether you are caught in the wilderness needing to collect rainwater to drink or just want to capture some rainwater for your flower beds, a sound rainwater harvesting system is vital. While collecting rainwater may make the difference between life and death, most of the time, it’s just a way to save money by giving gardeners a natural way to help the environment. So, what should you do when you don’t have a rooftop or gutters to help with your rainwater collection system? This article will explore some of the rainwater catchment techniques both survivalists and rain garden purists use to collect rainwater.

Table of contents


What Do I Need To Collect Rainwater?

There are three things you need to gather rainwater. First, you will need a rainwater surface area. Second, you need a means of transferring the water you collect into a diverter pipe (system) and toward a container. Finally, you need a place to store rainwater. Think of the three C’s. (Collection, Conveyance, and Container).

How To Collect Rainwater For Survival?

Here are several ways to devise a system to harvest rainwater outdoors when you do not have a roof or gutters to provide runoff or channel it into a storage container.

Use A Tarp System

Depending on where you find yourself (i.e., in a forest), choose a site near your camp where you can tie the tarp to a couple of trees or limbs (assuming you have rope, twine, or shoelaces). If you don’t, find a couple of young saplings that you can plant firmly into the ground and prop up the corners of the tarp).

You want to position the tarp to angle toward the container (pot, barrel, bucket, or whatever you decide to use as a final storage container). A canvas tarp is very porous, and water drips through the fabric. Polyethylene or nylon tarps are designed to be water-resistant, so you will need to angle the water flow toward the container or poke a hole in the center of the tarp for the water to flow from the tarp into the container.

An example of this method might be to follow the procedure that many UN refugee camps use. Refugees stick four posts made from tree branches into the ground in a space equal to the size of the tarp. They hang the tarp’s corners on each stick securely as if they were building a sun shelter. The rainwater funnels to the center of the tarp, dripping through the canvas to waiting containers below. (If you don’t prop up the center, but only the corners, the weight of the tarp should angle toward the center).

Another example of the tarp method is to attach a tarp to two parallel tree trunks at a higher level and then stake or tie the front of the tarp lower towards two other posts or trees. You want to be sure that you angle the tarp downward and leave enough slack for the bottom area to form a collection site or tie the tarp in such a way that it forms a V shape opening. The rainwater will run from the wide end of the tarp to the narrow end and into a container.

If you do not have a tarp, you could use a trash bag, a poncho, or another item, to capture rainwater. (You might have to put a small rock in the center to form a bowl for water collection). Many survivalists keep a sheet of polyethylene when camping outdoors.

Use A Bucket System

Depending on what is available, you can use a bucket or a basin for rainwater collection. Look for a way to form the ground or terrain to funnel more water into the bucket container to capture more water. (One survivalist suggests finding a large palm leaf or piece of wood from a hollowed-out tree that can be propped over the bucket’s edge and angled toward the container for water flow. You can also place a series of rocks on either side of a carved-out place in a hill to act like drainage pipes).

Use A Rock System

Water follows the laws of gravity just like the rest of the world. If you are near a rock cropping or seeking shelter in a cave, chances are that heavy rain will force the groundwater falling from above the cave entrance or outcropping to run off the rocks and down to where you can access it. Place your container where it can collect surface runoff and prop it up so that the rush of water won’t knock it over. Find a natural water channel that can be used as a conveyance system.

Use An Upside Down Umbrella

If you are camping, you might not have an umbrella, but it can be used to collect water for a drip conveyance system. Open the umbrella and hang it upside down from a low-hanging tree limb or the corner of your tent to act as a rainwater catcher. The inverted bowl will collect water and will likely drip from the center (you can poke a small hole toward the center, but chances are you won’t need to do so). Let the water drip into a bucket, basin, or bowl.

A Word Of Caution

Most surface water contains bacteria, viruses, and other nasty contaminants. Survivalists will be the first to tell you to treat water before consuming it. Chlorine dioxide tablets are some of the most effective treatments for making surface water safe for human consumption.

If you don’t have tablets, a tiny amount of chlorine bleach (four drops for each liter) or boiling the water in a running boil for at least a minute will kill the bacteria. This method is the best way to kill anything harmful inside your stomach. (Hopefully, you have enough water accumulated to boil it).

How To Collect Rain Water When Not In the Wilderness

Assuming that you are not in the middle of the wilderness but just want to collect rainwater for watering a few vegetables in your roof garden, you can use almost anything to catch rainwater. Again, design a system with the three basic things every rainwater collection system needs; a collector, some way to convey the water from one point to a collection site.

Use Rain Barrels

Many hardware stores and big-box home improvement stores carry rain barrels that can be used to collect rainwater. Set them in the middle of your yard where there isn’t much tree cover, and let it go. Most rain barrels hold 40 - 100 gallons and won’t cost you too much.

Use A Child’s Swim Pool

Here is a wonderful use for the kiddie pool your kid swan in at once. Most kiddie pools die an ugly death rotting in the corner of a backyard. Put them to work to gather water. (I had a friend who drilled a small hole in one side of the pool and another on the opposite lip. He hung the pool up, angled it down, put a rain barrel underneath the hole, and collected enough water to use in his garden).

Use A Rainwater Catch Pond

Some homeowners build a rain pond for harvesting rainwater in a collection area. You can dig a hole in the ground, line it with plastic and then install a drainage pipe or storm drains to channel other surface runoff into the catchment area. The collected water sits until needed for watering fields or other needs. Most municipalities have ordinances about the creation of rain ponds. They can also be susceptible to evaporation or stagnate from too much exposure to direct sunlight. In addition, soil erosion is a problem for rain ponds.

A Word Of Caution:

Standing rainwater can grow into stagnant water if it sits in a catchment area for any time. Do not allow rainwater to sit in a rain barrel or collection point so long that it becomes filled with algae or debris. In addition, if you live with mosquitos, the West Nile Virus is a real health hazard and can be deadly, so use the rainwater as it is collected.


Mark Walker

Mark Walker

I have over a decade of experience in food and beverage management, including a ServSafe food safety qualification. As part of this qualification, I have been professionally trained in safe food storage.

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