You may be surprised to hear but you absolutely don’t need a roof to collect rainwater. Sure, collecting from your roof is the easiest way to collect a large volume but there are plenty of methods to collect rainwater that don’t require a roof or gutters.
Broken down to its simplest essence, rainwater harvesting is made up of just a few key components: A surface area to collect rainwater, a system to direct the rainwater, and a storage container. These three elements can come in many forms and in the methods described below, they will.
How to collect rainwater without gutters
- Set out some barrels
- Rig up a tarp
- Utilize the landscape to your advantage
- Divert from your sump pump
- Condense the fog
Note: There are many ways that a person could collect rainwater, each with its own pros and cons. This article focuses on ways that you can capture and store rainwater for later use. Methods like rain gardens aren’t included as the water isn’t meant to be used later, though they are still a good idea.
1. Set Out Some Rain Barrels
Simply set out some barrels!
The solution doesn’t have to be complex and you don’t need to set up a whole interconnected system. Sure, barrels won’t have the same surface area as a roof or standalone catchment but they do have their own surface area and you don’t even need to come up with a solution to move the rainwater.
This is likely going to be the best option for those of you with small gardens or you just have some house plants that you’d like to water with rainwater (it is better for them after all)
2. Rig Up A Tarp
Without a roof, a tarp is going to be the cheapest, most efficient material to build a wide surface area. They’re only a couple of dollars each and they can cover a large area with just a few, though one should be plenty for most.
Because they’re waterproof, this is as simple as rigging up a tarp in some fashion. Whether it’s tied to a bunch of trees, your fence, or some other upright object, the tarp simply needs to take up as much area space as possible.
When setting up your tarp collector though, have a plan for how to collect the rainwater in a container. This could be as simple as having the tarp at an angle but if you do it this way, definitely get a funnel to reduce losing some from some of the stream simply missing your container. With a little creativity, there are plenty of ways to use tarps as your primary surface area.
Some people have gotten clever with their use of tarps to build different setups. This author posted an instructables page of an umbrella catchment made out of simple materials.
3. Utilize The Landscape To Your Advantage
It’s possible that your roof isn’t even your largest surface area, your land is! Depending on where you live, there is a good likelihood that your yard has a much larger surface area than your roof and might represent a decent opportunity to collect rainwater. In fact, this is how it was done for centuries!
There are a number of techniques designed to help manage the flow of stormwater from your land into storm drains. One of the most popular is a french drain. A french drain is a small ditch dug in your yard with a perforated pipe to help move rainwater off your property. In this case, you can also collect it instead.
Collecting rainwater from your land presents some challenges that aren’t present from your roof. First, there is going to be significantly more sediment and you will be required to filter your rainwater. Secondly, the laws of gravity are against you. If you are collecting rainwater that has already fallen and is traveling through a ditch, you will need to find a way to move that water from the drain into a storage unit. That could require a pump!
4. Divert From Your Sump Pump
One reddit user suggested a really clever solution: diverting from your sump pump!
In most of the other methods described, the goal is to capture rainwater as it’s falling but water goes through a long cycle even after it falls. A sump pump helps get rid of an excess of water that has come into your home and during heavy rains, can move a significant amount of water that you could be otherwise capturing.
Of course, the problem with collecting it after it’s fallen is that it’s not as clean as it would otherwise be. So if you end up taking this step, be sure to also have a filtration plan built into your storage system.
5. Condense The Fog
Okay, this one will not be realistic for most of you but it’s SUPER cool!
Engineers used the Aqualonis CloudFisher nets in Morocco to turn fog into clean water in one of the world’s driest regions in Morocco. According to Engineering For Change, these 3d printed nets can harvest between 4 and 14 liters of water per square meter of net.
How this works is the ‘net’ collects the tiny water droplets out of the area, like dew, but the net material isn’t absorbent. Gravity then does it’s job as the water droplets coagulate into larger droplets and fall off the bottom of the net into a gutter that directs the water to a storage system. This is most often used on mountains or hillsides where there is also a breeze. The existence of fog isn’t enough, the fog needs to move ‘through’ the net and so at least a little wind is also necessary for a fog net to work (also known as fog harp).
If you wanted to give a fog not a shot, here is a handy YouTube video that provides a DIY guide to build a small, inexpensive fog catcher that will get you at least some rainwater.