Despite the fact that rainwater remains one of the world’s primary sources of drinking water, for many people living in modernized areas the idea of rainwater harvesting has become somewhat divorced from everyday life. From the earliest parts of humanities history with settlements, rainwater collection has been a vital and essential tool. Today this remains as true as it did for our ancestors: the range of benefits to rainwater collection can be great. Yet despite that, rainwater harvesting has fallen so far from our everyday lives that many believe it to be illegal. This is (mostly) untrue – in all but one U.S. state, rainwater harvesting remains legal, with the caveat that some individuals have encountered resistance from minor local authorities.

There are a variety of methods of rainwater harvesting and a virtually limitless amount of uses for harvested rainwater. A rainwater harvesting system can take many forms: in its simplest form it is nothing more than a bucket left out to collect rainwater. More complex system can include extensive filtration, catchment tanks, and other professional solutions. On a broader scale, something like a fish pond or small reservoir can be considered a rain harvesting system.

Just about everyone can benefit from rain harvesting. A few of the potential benefits include:

Reduced environmental impact

Sustainable, self-sufficient renewable water supply

Reduced reliance on water companies

Savings on water bill.

Harvesting Rainwater: How To Collect It and What To Do With It

You probably don’t need anyone to tell you that water is useful. Yet when it rains, few of us look up to the sky and think a precious resource is falling on our heads. True enough that a few splashes of rain probably won’t benefit your day much, but collected into a rainwater harvesting system, what used to be an inconvenience has transformed into opportunity. Harvested rainwater can be filtered and purified to be used for drinking or cooking. It can be collected and undergo minimal filtration for use in washing dishes, laundry, flushing toilets or bathing. It can be used to water gardens and grow produce.

Depending on what you want to do with it, your rain harvesting system could be a simple DIY project or a complete system with high quality purification and filtration. Although we will touch on a few different uses for rainwater and harvesting systems, this article will primarily be concerned with collecting rainwater for hydration purposes – as that is the focus of the blog!

So to begin, let’s get one of the big questions out of the way…

Is It Safe To Drink Harvested Rainwater?

The simple answer is “maybe” – but that isn’t a very simple answer! There are many factors at play which determine if harvested rainwater is safe to drink. Where was it collected? How was it stored? What materials did it come into contact with on its way to storage? How long has it been stored? In theory, with the proper set up it is possible to harvest rainwater for drinking purposes with no additional steps, but we do not recommend this! While rainwater is indeed a clean source of water, there is more to consider. To quote this excellent article on rainwater harvesting from MIT:

“Rainwater is is a clean source of water; the quality of rainwater is often better than ground water or water from rivers and basins [11]. Rainwater is salt-free which means that it can easily be used for irrigation purposes without damaging plants and roots. However, atmospheric pollution due to high industrial and agricultural activities or traffic and contamination of the catchment surfaces are major issues as they contaminate the rainwater and make it unsuitable for drinking. Consequently, in many cities around the world, rainwater should not be used for drinking without prior treatment [11]. Additionally, especially in tropical and subtropical areas, storage tanks can provide a habitat for harmful vector diseases, bacteria, microorganisms and algae [2].”

While we would not recommend drinking rainwater without some additional steps for filtration and purification, it is something that is safe to do in many situations. Fortunately for us, we live in the world of technologically miraculous and surprisingly affordable filtration and purification systems more than capable of handling all the contaminants mentioned in the MIT quote above and more.



Filtering and Purifying Harvested Rainwater

As mentioned above, rainwater harvesting systems can be as simple or as complex as desired. For those who want to go the route of a complete installation in their home, large catchment tank systems are often the best route, ranging from hundreds to thousands of gallons in capacity. Integrated into your home plumbing, these systems can be treated with in-line filtration systems such as an APEC 5-Stage Reverse Osmosis Filtration System or something like the Amway eSpring Filter and UV Purifier.

While a system like this is massively convenient and capable of providing you with clean drinking water from your rainwater collection system at the twist of the tap, it is also quite a commitment and investment. It can require huge overhauls to your existing plumbing and can be pretty costly. Thankfully, those seeking a more affordable and DIY option for potable rainwater have plenty of options as well.

No-Installation Potable Rainwater Harvesting with a Countertop Gravity Water Filter

Instead of doing something as tedious as re-configuring your plumbing, there is an elegant solution to harvesting and drinking rainwater with just two items: a rain barrel and a countertop gravity water filter.

The formula is pretty simple: setup your rain barrel, wait for it to rain, and run your collected rainwater through your countertop gravity filter. Using a pre-filter of some kind is advisable, to prevent larger pieces of sediment or gunk from entering your countertop gravity filter. Quality rainwater harvesting barrels tend to have some types of small filters or meshes in place to keep larger debris from collecting in your barrel. A First Flush Water Diverter is another excellent addition, which diverts the first flow of water exiting the rain barrel, removing lots of contaminants that would otherwise mix with your water.

Something like the Big Berkey Countertop Water Filter System (~$300) is portable, has a massive filtration lifetime of 6,000 gallons (depending on the filter configuration used,) and most importantly is more than capable of handling any kind of nasty contaminants in your water. Designed to be capable of filtering water from raw, untreated sources, the Big Berkey has been tested as effective at eliminating all pathogens like bacteria and viruses while also eliminating a huge range of chemical contaminants. For well-harvested and stored rainwater, something like the Big Berkey packs more than enough filtration power.

For a look at some other countertop gravity water filter options, head over to our article Best Gravity Water Filters 2015.

A Brilliantly Simple Setup

Pictured above is the range of rainwater collection barrels available from Good Ideas Inc. Aside from making a stylish addition to your yard or garden, these affordably priced rainwater harvesting barrels can be a perfect companion to your countertop gravity water filter in the quest to make your rainwater reliably potable.

These Good Ideas rainwater barrels incorporate mesh screens to keep larger debris from entering your rainwater storage. They are constructed from durable BPA-free plastic and require virtually no installation: just set them up with access to water flow from your gutter or run-off system and let the barrel do the rest. For easy access to the contents, it might be a good idea to set the rain barrel up on an elevated platform so the bottom spout can be easily accessed without bending over. Alternatively, a Drinking Water Hose can be a great addition, letting you easily control where your water goes without worry. However, be sure to get a Lead-Free Drinking Water Hose, and not a regular Garden Hose. Drinking water hoses are made from food-grade plastics, whereas garden hoses are made from lower grade materials and can potentially contaminate your water supply.

With something like the Big Berkey Countertop Gravity Filter recommended above, it is easy enough to fill up the gravity filter’s 2+ gallon capacity by simply carrying some water in a container from your rainwater collection barrel and pouring it through the gravity filter. If desired, you can set them up next to each other and feed the gravity filter with your drinking water hose as required.

An All-In-One Rainwater Harvesting and Filtration Solution

If you are looking for something even simpler than a rain barrel and a countertop gravity water filter, you’d probably appreciate the simple convenience of the Shelf Reliance Deluxe BPA-Free 55 Gallon Water Storage System with Water Filter Pump. Although the Shelf Reliance barrel is marketed as a water storage barrel and not a rainwater collection barrel, it can easily be set up under your gutter outflow to collect rainwater. However, it doesn’t include any kind of mesh or pre-filter, so you’ll want to implement one to trap anything too large from entering the barrel.

Attached to the barrel is an Aquamira Plus BVR Filter with Emergency Pump which is capable of removing nasty pathogens like bacteria, cysts, and viruses, as well as any small particles and various chemical contaminants. This is a simple, self-contained, and almost zero installation solution to accessing potable rainwater harvesting.

If the idea of a “hand pump and barrel” system appeals to you, but you’re not quite sold on the Shelf Reliance barrel, you could opt for a different hand-pump water filter solution and any barrel of your choosing. Something like the hand-powered Katadyn Vario Portable Microfilter could easily get the job done and would allow you to use the rain collection and storage method of your choice.

Learn (Lots!) More About Rainwater Harvesting

We’ve just barely scratched the surface of the many possibilities of usages and systems for rainwater harvesting and storage. Mainly this article has focused on how to create a simple system for harvesting rainwater and easily purifying it for usage as potable drinking water. But the scope of rainwater collection is vast, and many brilliant ideas are available for you to explore and harness.

If you’re looking to purchase a rain water collection system or a water tank for containing your harvested rainfall, check out our Best Water Tanks for Emergency Water Storage or Rainwater Harvesting Guide to get a few great suggestions on water tanks and a bunch of helpful advice on installing, using, and maintaining your water tanks.

Below we’ve compiled a list of books and resources which we think will be helpful for anyone who wants to explore the topic further. There is a ton of information in the links below, everything from basic primers to DIY building guides to information on legal regulations and more.

Rainwater Harvesting Resources

Books

Web Resources

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Learn about the many benefits of rainwater harvesting and a simple method of harvesting and purifying rain water for potable usage.