With modernization comes a much higher standard of living, forcing some of the activities that were done in the past to be rendered obsolete by better alternatives. This includes gathering firewood, picking berries, or collecting rainwater, just to name a few.

However, in a survival scenario, a prepper knows it will be that those ‘old-timey’ skills and sustainability processes that will come in handy to sustain life. Those who are too engrained into the modern world will be the first to fall apart during a SHTF scenario.

In this article, you'll learn one of those aforementioned "obsolete" survival skills—rainwater harvesting—and why it's an essential skill, how you can practice it; effectively adding it to your survival skills arsenal for the all-too-crucial need for hydration.

What is Rainwater Harvesting?

Rainwater collection, or harvesting rainwater, is simply collecting the run-off rainwater from a structure to store for future use. When storm season hits, especially in Florida, it rains almost every other day. Collecting rainwater makes for the best use of the situation and utilizes mother nature's gifts.

Rainwater collection is often done through gutter channels on the roof. The rain pouring on the roof flows through the gutters and is then channeled into downspouts and collected into the storage vessel of your choice.

This water can be used in a multitude of ways. When purified, rainwater can be used for various household activities, including drinking and cooking. Since rainwater is quite clean, deep purification isn't always necessary, especially when used for irrigation, gardening, or laundry.

Collecting rainwater is often as simple as storing the collected water in a large barrel. But some people decide to step it up a notch and create elaborate harvesting channels that will store the water in large, pre-filtered cisterns that can supply the entire house.

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How is Harvesting Rainwater Useful?

Rainwater can be a life saver when fighting for survival. With the current depletion of freshwater resources across the globe, a better, more sustainable, and natural alternative may be just what you are looking for, whether for everyday use or just for preparedness sakes.

~Benefits of Collecting Rainwater

~There are so many reasons why you should consider harvesting rainwater as water is part of the Triangle of Sustained Life. As a prepper, you should take advantage of any sustainability hack nature has to offer.

  • You don't have to pay bills to access rainwater. The rainwater that you collect is 100% free. All you need to begin, is select a method by which to accumulate and store it.
  • Stored rainwater can be the primary source for household usage. If you aren’t ready for that level of commitment a simple barrel of it makes a great backup water supply for emergencies.
  • Collecting rainwater will enable you to live off-the-grid. You won't have to rely on public sanitation or government management to provide your home with running water.
  • For irrigation purposes, rainwater is a much more affordable and ‘cleaner’ option than tap water. This is because rainwater is free and not chlorinated. Unlike tap water, which tends to have amounts of chlorine for sanitization purposes.
  • When you collect rainwater, you have total control over your complete water supply.
  • Collecting rainwater can help you save money. Using solely rainwater or alternating between rainwater and tap water can drastically reduce or even eliminate your water bill.
  • Rainwater harvesting is the most responsible thing to do for the environment and gives you a big leg if SHTF.
  • The methods involved in collecting rainwater are relatively cheap to maintain and takes minimal effort on your part. Once set up, just let the rain fall.
  • Contrary to popular belief, rainwater is relatively clean. Depending on your uses, your filtering levels can range from zero for watering plants to filtered & purified for drinking and cooking.
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3 methods of collecting rainwater

The methods of harvesting water mentioned below all follow the same principle: rain falls and gets channeled into a water-safe collection basin.

The main differences boil down to uses, aesthetics, and budget:

  • Rain barrels
  • Dry systems
  • Wet systems

~Rain Barrels

~Rain barrels are the most popular method of collecting rainwater and most likely you've come across it at some point in time. The concept is easy to understand. An open barrel is placed underneath a gutter spout to collect rainwater.

~The rain barrel method is the easiest one to implement as a prepper may already have a barrel lying around. If one needs to be purchased, they are relatively affordable. They also don't take up much space as they nestle up against the side of your home.

~But before you go barrel hunting, it's important to know that the carrying capacity of a single barrels is limited. And as a result, there's the likelihood that the water might overflow during a heavy downpour.

~Dry Systems

~The dry system is like the rain barrel system in the sense that they follow the same concept. The 2 differences include that it has a larger carrying capacity than a rain barrel and is an enclosed container. The collection pipe "dries" after each collection because it's completely emptied into the tank, hence the ‘dry’ method.

~Due to its large water carrying capacity, the dry method is better at conserving water than the barrel method. This makes it better suited for individuals living in climates that experience lots of storm activity.

~Regardless of its size/carrying capacity, the dry method is also considered affordable. The average homeowner can install the pipe and container by themselves, and the maintenance isn't complicated or overly expensive.

~The problem with this dry method is that the tank must be located near your house. This may be a deal-breaker. Due to the size it can be conspicuous and it might look unsightly, especially for those worried about appearance or for those living in an HOA community.

~Wet systems

~This method, while being the most complicated, is the most rewarding. The wet rainwater system involves laying collection pipes underground to collect water from multiple downspouts. The rainwater will then fill the underground piping and the water will rise within the vertical pipes until it spills into the collection tank. These collection tanks can be stored above ground or underground.

~There are quite a few rules that must be followed when installing the wet system; the downspouts and underground collection piping need to have water-tight connections, and the level of elevation of the tank inlet must be below the lowest gutter in the house.

~With this method, barely any water is wasted because of the multiple collection streams. In addition to this, the tanks are generally extra-large, providing you the opportunity to collect and store large amounts of water. Unlike the barrel or dry system methods, you can keep the tank as far away from the house as you wish.

~One of the disadvantages of this method, however, is how expensive it is to install, largely due to its underground piping and size of the tank(s). An experienced individual could likely install this; however, the average homeowner may want to pay a professional, adding to the overall cost of the project. Additionally, precision is key here, if there is an insufficient difference between the height of the gutters and the tank, then the system want to work as effectively.

Filtering Collected Rainwater

Depending on how you plan on using your harvested rainwater, you will want to consider filter and purification methods. A great first step for all systems and regardless of expected use would be to install a gutter screen or cover that will keep our large debris like twigs, leaves, and bugs.

~Rain Barrel Method

~The rain barrel method will require more purification post-rain as the water often runs into an open barrel or a partially closed container. If you plan on using barrel collected water for hygiene or potable reasons pre-use filtering, boiling and other purification processes will need to take place.

~This system often lacks a ‘First Flush’ system since the gutter downspout pours right into the barrel. Regardless of use, basic water treatment is recommended even for this simplistic collection method. Adding chlorine or bleach to the bucket will help kill harmful bacteria and keep algae from blooming.

~Dry Systems

~Dry systems consist of closed containers. Closed container systems should always feature a ‘First Flush’ system. This will trap a certain amount of water from the very beginning of the storm, collecting the nasty bits that get rinsed off your roof with the first wave of water. Once the container gets full the remaining ‘clean’ water will continue on through a secondary filter of straight into the storage container.

~If a secondary particle filter is forgone, water treatment, pre-use filtering, and other purification methods will need to be taken for hygiene and potable uses. However, between the gutter screen and the first flush system, the water will be safe for irrigation and non-potable uses like flushing the toilet.

~Wet Systems

~Wet systems are almost always set up to be piped back into the home. Because of this, a wet system will often have all of the filtrations, purification, and water treatment systems in place. However, some may not realize, but despite all of the filtering that happens prior to going into the tank and the treatment that happened while being stored, there is still one more level of purification to be done.

~If you wish to use a wet or dry system to pump harvested rainwater into your dwelling for drinking water, dishes, or showering be sure to set up a whole-house filter. At the very least, install a reverse-osmosis system under your sink for drinking water and dishes. Based on the level of pre-container filtration, you may be able to get away with no filter for bathing.

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What are the uses of collected rainwater?

You can use rainwater in all the same ways you use tap water. The only considerations are the level of purification based off your desired usage:


~The Rainwater can be connected to your sprinkler systems so you can use the reserves to water your lawn. This will save you money by foregoing using your local reclaimed water sources.

~You can also collect the rainwater in watering cans and use it to water your garden, flower beds, or indoor plants.

~Cleaning Chores

~You can use rainwater to do your household cleaning. We aren’t just talking about your laundry; when filtered properly collected rainwater can be used for washing the pet, doing the dishes, and mopping your floors. Less purification is needed to wash your vehicle, clean outdoor furniture, or rinsing outdoor floors.

~Refilling Purposes

~Instead of wasting precious tap water, you can use filtered rainwater for refilling or topping up large water basins like your swimming pool, puppies splash pad, or your outdoor fountains. You can even opt to channel the pouring rain directly into your pool or other large outdoor basin.

~Indoor non-potable fixtures

~Properly filtered and treated rainwater can be useful for some non-potable fixtures. Prime examples include flushing the toilet, using the mess sink, or run the dishwasher.

~Potable Needs

~Rainwater can be harvested, filtered, and purified for uses in potable ways such as cooking, drinking, showering, and brushing your teeth. Any water being used for food, drinking, water that will end up near your eyes or in your mouth need to be fully filtered and purified to prevent parasites or other illnesses.

~Other uses

~You can use rainwater industrially and during manufacturing. Using rainwater during renovations tasks like wet sanding or to wet cut tiles, or even mopping garage floors. For businesses looking to become sustainable, a wet system can be set up to help supplement water uses for garages, shops, and other business-owned properties.

Calculating how much rain you can collect a year

There's no doubt about it, harvesting rainwater is a practice that everybody should embrace if they are a serious survivalist and/or looking for access to free usable water. You may be wondering what the output for all your hard work could be?

All you need to do is to figure out the square footage of your roof by measuring the footprint of the roof. For a more square or rectangular house, measure the width and length, then multiply the numbers. If you have multiple roof sections, then you should do this for each of section and then add the results together.

Once you've found the square footage of your roof, multiply it by 0.56. This will determine how many gallons you should collect per inch of rain. To find out how much rain you can collect in a single year, multiply the number from above by the average amount of inches your city gets of rain each year.