Living in the desert has taught me not to take water for granted. Unlike the Pacific Northwest, I am not footsteps away from streams, ponds, or a vast sea just waiting for me to collect and purify for personal use.
In a continuing effort to educate our readers on the finer aspects of self-sufficiency, I have invited Dan Chiras to share his best strategies and tips for creating a rain catchment system that works.
If Dan’s name sounds familiar, it is because he is the author of two Prepper Book Festival titles, Survive in Style: The Prepper’s Guide to Living Comfortably through Disasters and Power From the Sun: A Practical Guide to Solar Electricity. Today he is here with specifics on collecting rainwater, regardless of where you live.
Let it Rain: Collecting Rainwater from Your Roof to Survive in Style
In a crisis, rainwater can become one of a prepper’s greatest allies. If you live in an area with as few as 30 inches (12 cm) of precipitation a year, you may be able to live entirely off water falling on the roof of your home. That is, you could collect enough water from precipitation to meet all of your needs for cooking, cleaning, bathing, flushing toilets, watering gardens, and supplying a few chickens and a goat or cow – if you use water efficiently. I’ve done it for many years.
In drier climates, you may not be able to live off rainwater, but you could capture enough water to irrigate a vegetable garden and fruit trees and perhaps supply a few animals that provide the food you’ll need to survive in style.
Rainwater catchment systems are about as simple as they come. All you’ll need is a roof, gutters and downspouts, several rain barrels or a large tank (cistern), and water filters and purifiers. Chances are you are already well on their way to having a successful rainwater catchment system.
If your house is equipped with gutters and downspouts and you’ve got a water filter like an MSR Miniworks EX Microfilter and water purification device like a SteriPen, all you’ll need to do is to add a few rain barrels or a cistern connected to several downspouts to start collecting rain water right now.
I lived off-grid for 14 years in Colorado in the Foothills of the Rockies and supplied all of my family’s water with a rainwater catchment system during that time, although we used water very efficiently. I was constantly amazed by the amount of water we were able to collect off our roof. You will, too.
This 2500 gallon plastic tank was installed to catch rainwater off our roof.
How Much Rainwater Can I Collect?
To estimate the amount of rainwater you can capture from a rooftop, simply multiply the square footage of your home by the amount of precipitation in inches by 0.55. (IF your home is two stories, divide the total square footage by the number of stories.)
A 2,000 square foot (190 square meter) home in the Midwest in an area that experiences 30 inches of annual precipitation could capture 33,000 gallons (125,000 liters) of water per year. That’s about 90 gallons (230 liters) of water per day.
In most conventional homes, that’s only enough water for one person. If used judiciously, however, that 90 gallons (230 liters) per day could meet all of your and your family’s needs. (Judiciously is another way of saying you will need to use water very efficiently.)
How to Create a Water Catchment System from Rainwater
Here are some tips to create a successful rainwater catchment system.
1. Check with local authorities to be sure that rainwater catchment systems are legal in your state.
Some western states like Colorado prohibit rainwater collection, although I’ve known a few rebellious individuals who have installed them anyway, flying successfully under the radar. I can’t recommend that strategy, for legal reasons, but doubt anyone’s going to care if they’re capturing rainwater to survive. Even in “normal” times, illegal rainwater catchment is not a high-priority crime.
2. Remember, you can collect rainwater off your home, but also off roofs of other buildings such as garages, carports, sheds, and chicken coops.
Doing so will greatly increase your supply of water.
3. The cleaner the roof the better. Metal and tile roofs produce cleaner water than asphalt shingle roofs.
The cleaner the water, the less filtering and purification you’ll need to render the water drinkable. Bear in mind, however, if you’re going to simply use rainwater to irrigate gardens, fruit trees, and berry patches or supply a few chickens and a cow or goat, the water won’t need to be as clean up front.
4. If your home is surrounded by deciduous trees, install leaf guards on your gutters.
At the very least, install a leaf screen on your downspout. Leaves clog up gutters, but more important, decaying leaves in gutters produce organic compounds that contaminate water supplies. They probably won’t kill you, but they may turn the water brown.
5. For best results, install a roof washer.
This is a rather simple device that diverts a small amount of water initially flowing off a roof during a rainstorm away from your cistern or rain barrel. This, in turn, prevents dirt and bird droppings, if any, from contaminating your drinking water supply. (See the website I cited below to learn more about roof washers.)
6. If you live in a warm climate, rain barrels and cisterns can be installed above ground.
Be sure to install tanks with opaque walls (not clear or translucent). If possible, install them in shady locations to keep the water cooler and protect the tank from UV radiation. Tanks with transparent or translucent walls allow sunlight to penetrate. Sunlight, in turn, supports algae that will contaminate your water.
7. If you live in a colder climate and want to collect water from snow melting off your roof, be sure to bury your cistern below the frost line or place it indoors – for example, in a basement.
Only bury water tanks rated for underground burial.
8. If you are planning on drinking water from your system, it’s a good idea to install a tank rated for potable water, although a high-quality filter that removes organic chemicals may be all you need.
If you are going to be using the water for cleaning, watering plants, and supplying animals, a clean plastic tank will generally suffice.
9. If you purchase used tanks, be sure they have never been used to store toxic chemicals such as herbicides or insecticides or natural oils like Vitamin E.
The latter are very difficult to clean initially.
10. Rainwater can be emptied directly into open barrels from gutters cut off just above the rain barrel or can be filled by rainwater diverters that are installed in gutters.
It ain’t pretty but this simple two-tub system collects rainwater off one of our outbuildings to help water our cattle.
11. Be sure to place a fine-mesh screen over open rain barrels to keep mosquitos and other critters out.
They’ll lay eggs in standing water. Mosquitos are also potential carriers of some microorganisms that result in fatal diseases such as malaria, in tropical and semitropical climates. They’re also known to spread the West Nile virus in temperate climates. Lest we forget, they’re also a nuisance for those who like to sit outdoors at night. A screened top will also prevent birds and mice from gaining access and drowning, then rotting, in your water supply.
12. Place rain barrels on cement blocks and install a spigot so you can easily remove water from the tank with a garden hose or bucket.
You definitely will want to install a spigot on your rain barrel.
13. Remember, two or more rain barrels can be daisy chained (plumbed) together to increase the amount of water you collect.
14. If you install an underground cistern or an aboveground barrel or tank, be sure to equip it with an overflow – a safe outlet that will carry excess water away from the tank should it top off in a rainstorm.
Be sure the drains at least six to 10 feet away from your foundation.
15. If you draw water out of a cistern with an electric pump, be sure the inlet to the pump is six inches or so off the bottom of the tank so it won’t suck up any sediment.
16. Drain rain barrels and cisterns every year or two and clean them to remove sediment or organic residues that may have collected on the bottom of the tank or organic matter such as algae attached to the walls.
17. Purify water intended for human consumption – for example, water in which you cook food or water you drink.
Because rainwater collected off most roofs tends to be pretty clear (free of sediment or suspended solids), you may not need to filter it or it’ll require very little filtering. Do purify all potable water to eliminate potential parasites and microbes.
Additional Reading: Survival Basics: Water and Water Storage
18. After you have set up your rainwater catchment system, have the water tested for a wide range of contaminants, especially if you live in or near a polluted city.
19. Purchase filters and purifiers, then try them out.
Have the water tested again to determine how clean the water is.
20. Start learning many ways to use water more efficiently.
You can learn about them in my new book, Survive in Style: How to Live Comfortably through Disasters.
To learn more about roof washers and system design visit //extension.psu.edu/natural-resources/water/drinking-water/cisterns-and-springs/rainwater-cisterns-design-construction-and-water-treatment.
To obtain information on cisterns for personal water collection visit //www.rainharvest.com/rain-harvesting.html.
The Final Word
Rainwater catchment systems are perfect for those who want to stay put or for those who have a safe place to escape to in times of crisis but lack a water supply. Although you may have to use water very efficiently, for instance, by taking shorter and less frequent showers, you’ll be much better off if a short-term disaster morphs into a year-long nightmare than those who have simply stockpiled water. You can even use a rainwater catchment system in times of relative calm to reduce your dependence on well water or municipal water supplies.
Get going now and set up a system as soon as you can. This will give you time to learn how much water you can collect and how the system works. It will also give you time to work out any bugs. You’ll never regret this decision.
If you enjoyed this article, consider subscribing to email updates. When you do, you will receive a free, downloadable copy of our e-Book, The Emergency Food Buyer’s Guide. Also check the Facebook page regularly for links to free or almost free eBooks that we personally review just for you.
You can also vote for Backdoor Survival daily at Top Prepper Websites!
Bargain Bin: Below you will find links to the items mentioned and related to today’s article.
Survive in Style: How to Live Comfortably through Disasters: This is Dan’s excellent book on setting yourself up for a sustainable survival lifestyle. The chapters are laid out so you can tackle one major task a month, for sixteen months. An interview with Dan is featured in Prepper Book Festival: Survive In Style The Prepper’s Guide to Living Comfortably During Disasters + Giveaway.
MSR MiniWorks EX Microfilter: This portable water filtering system meets NSF protocol P231 for removal of bacteria (99.9999%) and protozoa (99.9%) from beginning to end of filter life in “worst-case” water. It will filter up to 1-liter per minute
SteriPEN Adventurer Opti Personal, Handheld UV Water Purifier: This compact handheld UV water purifier designed specifically for outdoor use. It destroys more than 99.9 percent of harmful microorganisms, including Giardia, bacteria, viruses and protozoa, and is is good for up to 8,000 liters
DryTec Calcium Hypochlorite, 1-Pound: This is 68% Calcium Hypochlorite. As of this writing, the price is under $10 with free shipping. I purchased Ultima Pool Shock which is 73% Calcium Hypochlorite. For more information, read How to Use Pool Shock to Purify Water.
Berkey Water Filter System: For in home use, nothing beats the Berkey. My own Royal Berkey represents a key component of my water preps. The Berkey system removes pathogenic bacteria, cysts, and parasites entirely and extracts harmful chemicals such as herbicides, pesticides, VOCs, organic solvents, radon 222 and trihalomethanes. It also reduces nitrates, nitrites and unhealthy minerals such as lead and mercury. This system is so powerful it can remove red food coloring from water without removing the beneficial minerals your body needs. Virtually no other system can duplicate this performance.
Need something from Amazon (and who doesn’t)?
I earn a small commission from purchases made when you begin your Amazon shopping experience here. You still get great Amazon service and the price is the same, no matter what.
Amazon has a feature called Shop Amazon - Most Wished For Items. This is an easy tool for finding products that people are "wishing” for and in this way you know what the top products are. All you need to do is select the category from the left-hand side of the screen.
Help support Backdoor Survival. Your purchases earn a small commission.
Author Bio: Dan Chiras has gardened since he was a tot and continues today sowing and reaping the benefits of his gardening proclivities. He lived off-grid in Colorado for 14 years entirely off rainwater catchment system. He powered his super-efficient home with solar energy and grew much of his own food. Dan continues to live a more self-sufficient lifestyle at his home and farm in east-central Missouri.
He is the author of 36 books on a variety of subjects including residential solar energy, wind energy, passive solar heating, green building, and self-sufficiency. You will find his books at //www.evergreeninstitute.org and at Lehman's.