Rainwater Harvesting: The Basics And Why You Should Start Today

Lead contamination. Chlorine and fluoride. E.coli. Fracking pollutants. Toxins and pharmaceuticals. There are so many things that might be mixed in the water that flows from the faucet, that turning on the tap may feel more like playing a chemical form of Russian roulette than getting a drink.

But what if I told you that there was a free source of incredibly soft water that is, for the most part, clean? Not from a river, not from a bottle, not from a filter, and not from a reservoir, rainwater has been an abundant gift of water for time immemorial. All you need to know is how to catch it.

What Is Rainwater Harvesting?

In order to talk about rainwater harvesting, there are two terms you need to first understand:

  • Impervious surface: A surface that is unable to absorb water.
  • Runoff: The rainwater that falls onto an impervious surface.

Rainwater harvesting is collecting runoff from an impervious structure and storing it away for later use.

In past and modern times, that impervious surface has ranged from canyon walls to roofs. Cultures across the world and across time have taken advantage of directing runoff for their daily use, from the jessour of Tunisa to the architecturally stunning jhalaras of Johdpur in India. The Isla Urbana project is an effort to capture rainwater in Mexico City to reduce strain on their aquifers, reduce flooding, and have a dependable source of clean water.

Stepwells are sophisticated water-harvesting structures built throughout India starting around A.D. 600, and used for access to water, social gatherings, and religious ceremonies. The ideas was that the long flights of steps could reach the ground water at its lowest, and as water rose during monsoons, the steps would submerge, sometimes entirely. This nifty, efficient system continued for over a millennium, gradually waning by the 19th century. With help from journalist and author @victorialautman, we added many of them to Atlas Obscura. Mahila Baag Jhalra is in Jodhpur, and was named for the beautiful and wealthy concubine who is said to have commissioned it. 📸: Photo by @victorialautman who has written a book on stepwells, “The Vanishing Stepwells of India.” Check out her account for more photos!

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Whatever the structure set in place, the mechanics are largely the same. Wait for the rainstorm, redirect and capture the rainwater, and use the abundance!

Harvested rainwater can be used for daily domestic supply, watering animals, growing plants, or saved for fire and emergency use. The storage methods will vary based on the intent of use, of course. Water used for fighting wildfires doesn’t have to be high quality, while water for drinking certainly does!

Getting Started With Rainwater Harvesting

First off, make sure it is legal in your area. If you live in a state that has regulations against harvesting free water from the sky, maybe it’s time to finally make the move to a homestead!

Establish Your Needs

Then, evaluate what your goals are for using your harvested rainwater and design accordingly. Do you want to collect water to ease the strain on your water bill? Create an independent source of safe water in the case of an emergency? Water your gardens and orchards with soft, free water? Switch over to using rainwater for your daily needs?

Each need will probably require a different system, so the next step is to do your research. Detailing the method, philosophy, and techniques of creating both short-term and long-term storage solutions for collected rainwater is far beyond the scope of this little article, so peruse this list of helpful and information-packed links to begin your journey.

Rainwater-Harvesting Resources

For a fantastic resource on rainwater-harvesting basics, instructions, and further information, check out this in-depth site.

For all your questions about storing collected rainwater, Art Ludwig’s your man. His books give detailed diagrams, instructions, and troubleshooting for building ferrocement storage units, cisterns, and natural water storage areas.

For those looking to jump in with two feet and create their own self-sufficient supply of collected rainwater, Michael Reynold’s Earthship books are irreplaceable. His experience-led diagrams, instructions, and philosophy behind his self-sufficient house designs are fantastic. So inspiring, in fact, that my husband and I are using his books to build our new house on our homestead.

There are also quite a few off-grid YouTubers and bloggers who have built and implemented rainwater catchment systems as their primary sources of water. “Off-Grid” with Doug and Stacy, “An American Homestead”, and Starry Hilder all have videos detailing their daily use of these independent systems, and most of them are active enough online that you could probably contact them with specific questions.

Rainwater Systems To Consider

I’ve listed the systems I’ve used and seen in order of intensity, from a weekend project for your garden to a full-scale, independent water system that you could depend on as your main water supply. If you’re seriously interested in harvesting rainwater, you’ll need to do lots of research and find out what methods are best for you and your land.

Rain Barrels

This is a weekend project that anyone could benefit from. You can buy a rain barrel, or you can DIY your own. Our rain barrel in the city was a food-grade, 50-gallon barrel that had once held jalapeño peppers!

You’ll need to install a water diverter onto your downspout, connect it to a rain barrel or three, and wait for a rainstorm. Your backyard garden now has rainwater, even on a sunny day!

Please note: Raw rain barrel water, especially water collected from an asphalt-shingle roof, is not suitable for human consumption without processing.

If you’re looking for something to store more water, tote bins—used for palletized, bulk transport of liquids—are usually made out of food-grade plastic and can hold 275 gallons. You can often find them on Craigslist. We’re currently installing two of these on our barn to collect rainwater from the metal roof.

Rain Gardens

You know that soggy part of your yard? The low, little spot where rainwater collects and kills all the grass?

Rain garden. #gardening #gardens #raingarden #flowerstalking #flowerbed #ladner

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Or what about that area at the end of your downspout that gets flooded with every thunderstorm? These are areas begging to be turned into a rain garden.

Swales

Swales go by many different names around the world, but their function is the same—to stop runoff from flowing down a hill and allow it to soak in instead.

Swale suckin it up… #swale #savethewater #slowthewaterdown #oncontour #design

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Installing swales on the slopes of your land stops erosion, can allow you to multiply your available garden areas and could help direct rainwater into your new gardens (rather than the neighbor’s yard).

Ponds

A pond is a fantastic source of stored rainwater, loaded with beneficial organisms that keep it from going stagnant.

commercial rain water pond
A plastic lined pond for rainwater collection in California. U.S. Department of Agriculture / Flickr (Creative Commons)

Though the water will need to be purified for human consumption, creating and maintaining a pond on your land will ensure that you and your animals can have access to naturally stored rainwater in times of need.

Tanks And Cisterns

Having a place to store collected rainwater gives you the assurance of having water whenever you need it, from the 5-gallon water cooler to the 10,000-gallon cistern half-buried in the backyard.

#rainwaterharvesting #cistern #communitygarden

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The range and scope of how to use these ancient and modern water storage units are worthy of an article (or twenty) in its own right. Art Ludwig’s book Water Storage: Tanks, Cisterns, Aquifers, and Ponds is a fantastic resource for finding the right project for your needs.

Benefits Of Harvesting Rainwater

Whether you’re living entirely off-grid or are just getting started with urban homesteading, rainwater harvesting offers a host of benefits.

Water Security

One of the main benefits of harvesting rainwater, in my opinion, is water security. Our first winter on the homestead, before we started work on our house, we lived in an older trailer. When the aging electric pump went down, we were without water for ten days. We kept our house running—and all of our animals watered—with the combined help of a neighbor, the laundromat, and water from our local store, but we became sharply aware of our vulnerability.

rainwater harvesting barrels
jbolles / Flickr (Creative Commons)

If the roads had been blocked, for example, our only option would have been to chip ice out of the pond and melt it on the wood stove. The pond does offer some water security, but after that ordeal, we knew that we wanted to be able to harvest and store rainwater (and get a manual pump!) so that we’d never have to face that situation again. Directing rainwater to a cistern or storing it in a pond are two ways to ensure that you have secure access to a water supply if your pipes get contaminated or run dry.

It’s An Alternative Source Of Water

In urban environments, rainwater harvesting both reduces runoff and provides an alternative source of water that reduces stress on what is often an over-taxed, outdated sewer system. In highly developed areas, rainwater is flowing over rooftops, pavements, asphalt roads, sidewalks—everywhere that humans have cut off the rain’s access to absorbent ground.

As that water flows without permeating, it picks up everything on the surface—gasoline, animal feces, garbage, oil, lawn fertilizers, and road salt. All that polluted water is dumped into sewers.

Out of sight out of mind, right? Wrong. Most cities still have old-style combined sewers, meaning the raw sewage from household use combines with road runoff into a single pipe as it heads to the water treatment plant. Whenever it rains, the massive amounts of runoff overwhelm the water treatment plants, resulting in an emergency action called a “Combined Sewer Overflow” or CSO.

red rainwater barrel
With a rainwater collection system you’ll know exactly what is in your water. Paul Sableman / Flickr (Creative Commons)

In layman’s terms, that means that the excess water is dumped straight back into whatever bodies of water are accessible—rivers, bays, oceans. Yes … you read that right. Straight-up human poop, gasoline, and toxins are flushed, untreated, into natural waterways when it rains. Every time.

Trust me, I used to teach classes along the Cuyahoga River—when your classroom is near a river that caught on fire 13 times, the reality of runoff pollution is a lot more visceral!

Gathering urban rainwater for use in gardens is an itty-bitty way to mitigate all that runoff. It doesn’t do much on an individual scale, but it could do something on a massive scale! Creating urban infrastructure that slows down, captures, and uses rainwater is called Low-Impact Development. Interested? There are many beautiful and useful ways to stop urban runoff; check out this link to learn about pervious pavement, bio-retention cells, rain gardens, green roofs, and more!

Rainwater Is Soft

Another benefit of rainwater harvesting is the nature of the rainwater itself. “Rainwater is especially suited for hair washing, laundry, and flushing salts from the soil due to its extreme softness.” (Water Storage, Ludwig, p .7) I can personally attest to this! After our move to the country, I unexpectedly found myself with totally unbrushable hair.

No matter how I washed it, our well water was unbelievably hard, leaving a greasy, gray film on every strand. Feeling frustrated, dirty, and out of options, I waited for a storm, filled a bucket, and washed my poor head. The difference was instant! I literally pulled that gray goo off my hair (gross!), finally felt clean, and have been happily washing with rainwater ever since.

Written by Michelle Shall

Michelle and her husband recently escaped from the confines of city life and moved their family to 12 acres in the Missouri Ozarks.  They are currently in middle of establishing their dream of a self-sufficient, off-grid homestead.  She can be typically found knee-deep in brush, foraging for wild edibles, cooking on cast iron, hugging her favorite chickens, chasing her kids, sporadically waving her arms to emphasize a point, and, in quiet moments, sketching and painting.

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