If there is one precious resource that is ever at the front of a prepper’s mind it has to be water. Sure, most folks are more emotionally preoccupied with food but that’s because the water in our era has become so plentiful and so safe it is relegated to an afterthought. That is, until you are ready for a drink and don’t have any…
Considering that you can only go for a couple of days at most with absolutely nothing to drink before perishing special emphasis must be placed on obtaining and storing water as part of a well-rounded survival plan.
Beginning preppers will invariably rely on huge quantities of bottled water, but preppers who are more seasoned and focused on logistics will set out to collect water from reliable natural sources.
One of the most abundant, cleanest and best sources of natural water is taken from a passing shower or thunderstorm. Imagine having hundreds and hundreds of gallons of water on hand for:
- Washing your car or home
- Running fixtures like toilets and sinks
- Watering livestock and pets
Catching and storing rainwater has been used as a primary or secondary source of water by cultures all around the world for ages, and it is still entirely viable for the same purpose today.
Setting up a rainwater collection system might sound like a major undertaking, but believe it or not, with just a little bit of education it is far easier and more affordable than you might be thinking!
In this article we’ll be presenting all the information you need to develop a foolproof plan for your own rainwater collection operation.
Table of Contents
What is Rainwater Collection?
Rainwater collection is exactly what it says it is: The gathering and storage of natural rainfall. Although in a strictly literal interpretation rainwater could be collected from a source standing on the ground or another surface, it is most popularly gathered as runoff from a roof or purpose-built structure and then directed into a storage container, large or small.
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The basic components of any rainwater collection system are:
- Roof (or other catchment structure)
- Gutters (to direct the caught rainfall)
- Inlet Piping (to transfer water from the gutters to the tank)
- Tank or cistern (to store the water for later use)
The beauty of rainwater collection systems is that they are entirely scalable; a camper or hiker could set up a rainwater collection system using a tarp or sheet plastic, and then form it into a simple funnel to direct it into a canteen or other drinking container.
On a much larger scale, farmers might employ huge collection systems that can source hundreds or even thousands of gallons of rainfall to supplement their primary supply of water for irrigation.
For our purposes, rain can either hit the ground and wash away, or we can seize the initiative to catch it, collect it and store it to be used for any number of purposes, including drinking.
Rainwater Collection is Increasing in Popularity
Compared to bygone eras in history and current, specialist purposes around the world today, rainwater collection is quickly becoming a common endeavor both in residential and commercial applications, rural, suburban or even urban settings alike.
It might have taken a little while, but even everyday people are waking up to the notion that rainwater collection is an excellent idea, not just for the practical purposes of preparedness or reducing the cost of public water but also as an environmentally friendly way to make the best possible use of a precious resource.
Consider the following:
Rainwater Collection isn’t Just for Farming!
Most folks are familiar with the collection of rainwater in our country for use in the irrigation of cropland. It is the rare farm that does not have at least some supplementary water supplies sourced from rainwater.
In certain areas, collective rainwater can even form the primary source of water for use and irrigation and other tasks around the farm. However, rainwater collection is useful for far more than just this!
Even a modest rain catching system located on a home and an area with ample rainfall can easily supply the vast majority of a home’s water needs- for washing, for the flushing of toilets, bathing and even drinking.
This can make off-grid living far more viable, or just save a ton of money over the long run compared to the use of public utilities.
Naturally, preppers will be interested in storing rainwater since it will serve as an abundant, free and overwhelmingly safe source of water in the event that typical supplies are compromised or merely run out.
Rainwater Adds-Up Quicker than You Think
Sure, everybody understands that you’ll get wet pretty quickly if you go outside while it’s raining, but it seems like it rarely rains hard enough most of the time to add up to any meaningful amount of water.
Yeah, you’ll see a few puddles on the ground and maybe a little bit of standing water in drainage ditches and the like but how much water can you reliably harvest from a passing shower or thunderstorm?
As it turns out, a lot more than you think! Just one inch of rain over a single square foot adds up to a tad less than 2/3 of a gallon (actually 0.623 gallons).
That is a fair bit of water for drinking, in reality, so just imagine how much more you’ll collect, and how quickly, when you have dozens or hundreds of square feet worth of rain water accumulating, all of it being piped into your storage tank!
Even if you are relying on a household rainwater collection system that is fed off your roof you can wind up with dozens or hundreds of gallons of water after just a few days worth of modest rainfall.
And all of it stored in a system capable of supplying your home with water as normal or at the very least being easy to access and put to use.
That is capability that no prepper can afford to ignore!
Uses for Harvested Rainwater
Harvested rainwater is obviously thought of as a primary or supplementary method for irrigating crops, be it a large working farm or a small at-home garden. But this is not all that harvested rainwater is good for. Consider the following potential uses:
- Washing home, vehicles and equipment: Rainwater should be your first choice for washing your home, your vehicles and any other items and equipment, from tools to dishes. Most holding tanks can easily be set up to feed the required equipment like garden hoses or even pressure washers using an easy to install pump.
- Washing people and pets: When it comes time to bathe most rainwater that has even undergone simple filtering is more than clean enough for washing people and pets. In a survival situation or just during a drought to be a water-miser you’ll be glad you aren’t sacrificing drinking water for other purposes. Collected rainwater is perfect for the task.
- Supplying fixtures: Is public water that is offline, shut down or too contaminated to risk using? A residential rainwater collection system can easily be set up to supply interior and exterior fixtures as normal. Showers, sinks, spigots and toilets can all make use of rainwater drawn directly from your storage tank.
- Drinking: This might come as a surprise, but rain water is entirely suitable for drinking, though you would be well advised to filter and potentially sterilize it first. Since rainwater is going to be gathered most likely off of a roof based system any dirt, detritus and other assorted nastiness found on your roof could make its way into the water. Nonetheless, it is almost invariably far cleaner than natural water sourced elsewhere.
- Irrigation: Whether you are watering a small garden or a huge plot of crops, you’ll need lots and lots of water. One of the only plausible methods for accomplishing this, assuming you lack a large body of water conveniently on your property, is to make use of large rainwater collection systems. Especially in an SHTF situation, making the best possible use of rainfall is one of the only ways to ensure you’ll have the necessary amount of water to support irrigation at the required intervals.
- Hygiene: Hygiene is an essential consideration for long-term survival, not to mention your sanity and emotional wellbeing! Sadly, many preppers and survivors of disasters see it as a nicety or afterthought, owing to the notion that water is too precious a resource to waste on such things. But if you have dozens or hundreds of gallons of clean water on hand and ready to draw from you won’t have to miss many, if any, showers or baths, especially if you live in a rainy environment where your next “refill” is just a few days or weeks away.
- Watering Livestock or Pets: Our animal companions and charges need water too, and more than you think! Domestic dogs and cats need their own water supply the same as people, and if you are caring for large flocks or herds of livestock- cows, sheep, goats, chickens, pigs, horses, etc.- you’ll need dozens of gallons of water every day just to make sure they are hydrated. A huge tank full of rainwater is just the ticket, and sure to take a load of worry off your shoulders.
There is a lot that you can do with rain water. The trick, of course, is collecting it in quantity! Lucky for you we will show you how in the very next section.
Assembling and Installing Your Rainwater Collection System
Assembling a rainwater collection system is a fairly simple affair, though depending on the nature of your property or the desired system it might not be easy!
At any rate, this is a project that is well within the reach of most DIY’er preppers who have access to a vehicle capable of relocating the sometimes large and fragile storage tanks.
For some installations, digging might be required and some supplementary light construction such as the creation of a concrete pad or other suitable spot for the tank or tanks.
The good news is that most systems are highly flexible and modular or semi-modular in nature, meaning a solution is achievable for nearly any circumstances imaginable, and most will work plenty well off of any existing roof and gutter system.
If you decide to implement more storage you can tie an additional tank into the system or replace the existing tank with a larger one.
If your house or structure lacks gutters, you can install your own easily enough. Better yet, these systems are rarely permanently installed, meaning if you relocate you can bring your system with you using nothing more than a little extra elbow grease.
Read the following sections to learn what is required for implementing a rainwater collection system on an existing home or small commercial space. Optional components are indicated accordingly:
Components of Traditional Systems
Roof: Collecting rainwater in a typical residential setting begins on the roof of your home. Rather, your roof is actually the lead component in your system! Rain that strikes your roof starts to head downward, and channeling water in the direction we want it to go is the first step in gathering it.
Note that pretty much all modern roofs are entirely satisfactory for the purpose of gathering rainwater, though certain ones are better for the job than others, owing to less contamination from particulates and other substances.
Gutters: Gutters are another ubiquitous feature on modern homes, and typically serve to direct rainwater away from your home’s foundation in a tidy fashion. You don’t need special gutters to funnel your rainwater towards your collection tank but you might need to make a few modifications to them so they are up to the job.
Specifically, the installation of a diverter may be required as well as the installation of a fully enclosing guard or cover system to keep large debris out of your water and hopefully out of your filtration system.
Something else to consider is that most residential gutters have several downspouts located around the perimeter of the home.
It is worth considering modifying or tying the gutters together at the roofline to divert more rain water to the tank although this might require additional reinforcements to handle the increased volume.
Tank / Container: The tank, or container, is usually the most obvious feature of a rainwater collection system.
Rainwater tanks come in all shapes and all sizes, and are made from a variety of materials, with the resulting matrix producing a truly bewildering number of styles and types.
Suffice it to say they all have advantages and disadvantages, but the important thing is that you should take comfort knowing there will be a tank that is just right for your application no matter what your purpose is.
Depending upon your property and desired outcome the tank might need to be located right next to your house or some distance away on your property. There is a lot more to learn about tanks, so we have included an additional section about them below.
Overflow Pipe: An overflow pipe allows excess water to drain out of your tank in order to prevent overfilling and the associated problems of excess weight and backup into your inlet.
An overflow pipe might simply allow the water to spill out onto the ground or might direct it via a subordinate gutter safely away from the foundation of the tank or your home. This might be an included feature in your tank or an optional add-on.
Water Level Gauge (Optional): No surprises here, a water level gauge allows you to easily determine how much water is currently in your holding tank, exactly or approximately. Water level gauges come in analog varieties relying on floats or other apparatus or they might be digital in nature, capable of furnishing a precise reading.
Generally helpful, especially for preppers, as this can allow you to easily determine how much water is entering your tank after a given amount of rain or how much you are using for any particular purpose.
Rain Head: The rain head is essentially an oversized downspout installed at the lowest point of your gutter system. Compared to a traditional downspout system a rain head will usually tie your existing gutters into round piping for transporting the water to the tank.
First-Flush Diverter (Optional): A first-flush diverter is a device that will allow the initial rush of oncoming rainwater to exit the system and drain away prior to entering the storage tank.
This is because the initial onset of rain will bring with it all of the debris, germs and other assorted detritus present on the roof and lurking in the gutters that you definitely don’t want going into your tank.
Instead of relying on your filter to catch this stuff you can just purge it from the system, greatly improving the overall quality of your collected water and the lifespan of your filtration systems.
Rain Head Filter (Optional): A rain head filter installs in the rain head, just like the name suggests, and helps keep larger debris out of the rainwater headed for the storage tank.
The other filters are commonly employed in rainwater collection systems, particularly those intended to supply water for residential use or drinking, this is a common and important upgrade. Like any filter, they must be regularly inspected, cleaned and if necessary replaced.
Tank Screen: The tank screen is the last line of defense against contaminants in the water heading into the tank, and is installed immediately prior to the tank inlet.
The tank screen is especially important as it not only helps keep out larger debris, but also pests such as rodents and mosquitoes that can easily contaminate your water severely! These are a common feature of many tanks, but aftermarket versions that offer enhanced capability are popular.
Pump (Optional): A pump system allows you to pressurize the rain water heading out of your tank for any purpose, making it able to supply tools and irrigation systems or even multiple outlets in your home more effectively than it would using “gravity” feed alone.
Choosing a pump for any variety of purposes is another topic in itself entirely, and depending on your application you might need to install standby systems or other accoutrement to make it viable.
Outlet Filter (Optional): Yet another filter that you can install in your rain collection system, although this one is installed after your pump so maybe it isn’t part of the rain collection system proper! Consider this a must for any pump that is supplying household piping.
Auto-Fill System (Optional): An auto-fill system is designed to engage and fill your rainwater tank up to a specified minimum level using any other source of water connected to the system, but typically public or well water as usual.
At first thought, this might seem sort of backwards with the purposes of your rainwater collection system but when you consider that many folks utilize their rainwater tank to supply full-time or automated irrigation systems this makes sense; pumps could be burned up if the rainwater tank is allowed to run dry!
Think of this as a safety system for protecting pumps connected to your main tank.
Improvised Collection Systems
When talking about any rainwater collection system, especially in the context of personal readiness, improvised systems must be discussed.
The purpose designed and commercially available components for the system described above are undeniably efficient, relatively easy to install and long-lasting but they aren’t the only way to skin this particular cat.
Anything that you can cobble together that is capable of catching rainfall over a wide area and then directing it into a container will do the job of furnishing a considerable quantity of water anytime it rains.
Sure, it might not be nearly as efficient and not half as attractive as a cleverly designed commercial system, and it might lack built-in filtration or other purification methods but it will keep you hydrated and keep the water flowing for irrigation.
Systems of this type are limited only by your imagination, but effective rain catching systems can be created using nothing more than scrap boards or branches and heavy tarp or mylar plastic sheeting.
You can also go really low tech and simply set out a variety of containers to catch rainfall or runoff emerging from other surfaces. A few variations you might try:
- Large plastic containers set out to catch rainfall directly.
- Kiddy pools are ideal for the purpose.
- Large funnels connected to articulated plastic tubing.
- DIY trough made from plastic paneling.
- Use a clean plastic trash can; invert the lid, drill holes in it, and cover with mesh screen.
For some of the more basic methods you’ll need to work fast and cautiously to collect the water in a larger, central holding tank if desired. Also note that any open containers are highly vulnerable to contamination, particularly from mosquitoes and rodents.
Tank Types and Selection Considerations
As mentioned above, the storage tank is a central component in any rainwater collection system. One factor you’ll need to spend some time figuring out is the ideal size and type of tank for your needs and for your property.
It is bad to have a tank that will hold too little water but it can be just as bad to have a tank that holds too much.
There is no other way around it: Most tanks are eyesores and even though they can be dressed up with decorative facades or cleverly hidden behind obstructions or terrain features, most of them take up plenty of room.
There are specialty tanks that can be buried or otherwise hidden, but these present additional technical challenges that might make the juice unworthy of the squeeze.
Another consideration in tank selection is the material they are constructed of. Polyethylene (plastic), fiberglass and galvanized metal all have advantages and disadvantages, and these should be carefully considered in light of your budget and desired outcomes.
Read up on the following tank formats and types below so you’ll be better informed when the time comes to install your own system:
One of the smallest and least obtrusive containers, a rain barrel is exactly what it says on the label- a barrel that holds captured rainwater. Typically placed very near an existing downspout, there is virtually no property that won’t have room for an added rain barrel or two.
Most barrels hold between 55 and 100 gallons of water, and though that seems like a lot (at least if you are drinking it) that amount of water will not last long for irrigation, washing and other chores.
Despite their small size rain barrels are popular as introductory or supplementary systems particularly if you are able to use a switchable inlet system or connect barrels in a series.
Wet Collection Tanks
Wet collection tanks are so named because the supply pipes that feed the tank remain wet (containing water) after the tank is filled.
Typical wet collection systems feed multiple downspouts from the gutter system to an underground network of pipes that travel to the storage tank typically located some distance from the structure.
As long as the intake of the tank is situated below the lowest gutter on the structure that is collecting the water, the tank will fill normally as long as it is raining. Once the flow of water stops some water will remain in the below ground pipes, hence the “wet” moniker.
Compared to other systems, a wet tank system is somewhat more complex to install since the piping is situated below ground and ensuring watertight connections is imperative.
However, it is a great way to unify an existing gutter system for the purpose of filling a storage tank and it helps cut down on above ground piping which is invariably an eyesore.
Dry Collection Tanks
A dry collection tank is one that is typically situated immediately next to the structure that is collecting and directing the rainfall.
Dry collection tanks get their name from the propensity of the inlet pipe to dry after the rainfall has ended since they typically empty directly in the top of or near the top of the storage tank with no leftover water standing in them.
Compared to wet collection tanks, dry tank systems are easier and cheaper to install since there is no need to bury piping or locate the tank any significant distance from the structure.
In addition to lower cost, maintenance is usually simplified, but the obvious trade-off is that these tanks are (still) eyesores and can also create problems when work must be done on the structure behind or near the tank.
However, the tremendous capacity of these tanks, usually several hundred gallons or even more than a thousand, often makes them an attractive option for those who want a drastic amount of water on hand for an emergency, full-time supply of the household or irrigation purposes.
Beyond the tank systems described above, the storage tanks themselves are available in a dizzying array of materials and physical configurations capable of suiting any desire.
If you want a low profile above ground tank that is inexpensive and will easily fit under the eaves of your house, there is an option for that.
If you want a tank that is completely out of sight so it doesn’t spoil the view of your beautiful property or attract attention from nosy neighbors, you have several options to accommodate that as well.
The following is a respectable selection of some of the most common material types and physical configurations for water storage tanks suitable for inclusion in a rainwater collection system:
Polyethylene plastics are the most common type of plastics available and an extremely popular, budget-conscious choice for water storage tanks.
Available in a variety of form factors, sizes and colors polyethylene is a good choice for all around durability, portability when empty and performance, as they can be had in food grade or non-food-grade varieties.
Polyethylene is popular for those who want a DIY install as they are easy to transport, and since they are plastic they won’t rust, easing maintenance concerns.
However, polyethylene plastic tanks are extremely vulnerable to high temperatures particularly fire and relentless exposure to UV will steadily degrade them over time even if they are manufactured with a UV resistant additive or coating.
Note that any polyethylene water tank should be completely opaque, not even a little translucent, as otherwise algae will bloom readily and rapidly inside your water.
Fiberglass tanks represent a sort of halfway point regarding the advantages and disadvantages of both polyethylene and metal water storage containers.
They are generally economical and physically durable, like polyethylene, but are significantly heavier and generally it must be craned into place.
Fiberglass tanks can be had in food grade varieties making them an excellent choice for drinking water storage, and they’re smooth exterior is easy to paint, meaning your tank can be painted to match an existing structure, painted in an attempt to camouflage it or even artistically decorated to suit any taste.
Again like plastic, fiberglass will degrade steadily with constant UV exposure, though not as fast as plastic, and depending on where you live a suitable fiberglass tank might be difficult to locate or expensive as manufacturing of such tanks is not nearly as widespread as their plastic competitors.
Fiberglass tanks are also not commonly available in as many form factors as plastic.
Galvanized metal tanks, or cisterns, are a popular and traditional option for water storage, though they can be more expensive as the size of the tank increases.
Typically attractive with no painting required (or at least charming in appearance), they are suitable for aesthetically-pleasing installs on a variety of properties.
Notably, metal tanks will not degrade in any meaningful way from exposure to the sun even after decades of UV exposure, though rust will still be an ever-present concern, and special care must be taken to keep water from accumulating on the exterior of the tank.
Though galvanized metal tanks are not inherently suitable for storage of drinking water they can easily be converted for such a purpose by installing a food grade, appropriately-rated liner system.
Metal tanks are also worth investigating for a DIY install as they are surprisingly light when empty, though they are equally vulnerable to denting and difficult to repair should such an accident occur.
For folks who are working in a very tight footprint or who just want a proper tank with a small and unobtrusive form factor a slimline tank is the solution.
Easily identified by their “pill” shape, slimline tanks can be had in polyethylene or metal varieties and are among the smallest legitimate tanks, affording up to 500 gallons worth of rainwater storage. That is significantly more than a typical rain barrel, but much less than larger, full-sized tanks.
The combination of attractive and unobtrusive form factor in conjunction with their feathery light weight means these are one of the most attractive options for DIY installers. Note that if you are a power user of your collected rainwater you’ll empty one of these very quickly.
If you want a water storage tank that is either completely out of sight but not underground or want a tank totally protected from UV degradation then a pillow tank is the right solution. Pillow tanks get their name from their shape, looking for all the world like a pillow lying flat on a bed.
Originally designed for folks who wanted to install their tank beneath a deck or a crawl space beneath their home, they have also found a following with those who want total protection for their water from the sun’s rays.
The major disadvantages with pillow tanks are that they are extremely difficult to clean out and maintain, and for that reason should depend on the best filtration technology available. They may also have an extraordinarily large footprint since typical installation beneath a deck or home means there is a distinct vertical limit for the profile of the tank.
For those who are unwilling to settle on plopping an ugly, obtrusive tank on their property or near their home, a decorative storage tank solution is demanded.
This will obviously constitute a significant increase in cost depending on the materials used but may be worthwhile for those who have considerable social pressures in the form of a regulatory body or agitated neighbors.
However, a decorative tank veneer brings more than just good looks to the table: No matter what type of tank you have, a wood or masonry veneer will completely protect the tank and its contents from exposure to UV, greatly increasing the life of the tank and also protecting the water within from forming algae or other undesirable life.
Underground tanks, available in both fiberglass and polyethylene varieties, are a specialized installation that possess just as many unique advantages as they do disadvantages.
The most obvious advantage of an underground tank is that it is completely out of sight, but more practically it also helps keep the water inside the tank at a constant temperature and also completely protects both the tank itself and the water within from UV degradation.
Believe it or not, an underground tank full of water will not freeze in most locales since earth is such an excellent insulator.
Aside from an upper layer of frost in the soil, the water will remain liquid so long as the tank is installed to an appropriate depth. You will always have to take care with any above ground piping, however!
However, underground tanks require considerably more labor and logistical support to install since they must be installed into an excavation and subsequently piping must be run to them.
Additionally, the tanks must also be kept full so they will remain in place, empty or nearly empty tanks can float out of the ground during heavy rains.
One must also be cautious to ensure that the underground tank is not walked over as this can dent or collapse the tank below the surface, depending of course on the rating and installation of the tank itself.
A Note on Legality
By now you are probably pretty jazzed up about installing your very own rainwater collection system and I don’t blame you: The benefits definitely outweigh the cost and hassle for most people living in most locations.
But, as crazy as it sounds, you should know that quite a few states actually have restrictions regarding catching rainwater.
It’s true: apparently some state governments are so supremely arrogant they think that even rain that forms in the sky belongs to them before it belongs to us. Restrictions exist on everything from the type of installation that you may use to catch and store rainwater to what you can use the rainwater for.
For instance, Colorado mandates that citizens may only collect up to 110 gallons of rain water in no more than two rain barrels and that that water can only be used for outdoor purposes.
Even in Georgia of all places the state mandates that rainwater collection be closely monitored and regulated by the Department of Natural Resources (Environmental Protection Division) and only used for outdoor purposes.
Illinois, ever on the cutting edge of big government intrusion into private affairs, specifies that the harvesting of rainwater be done in accordance with the Illinois Plumbing Code and only used for non-potable purposes.
Other states abound, but these are some of the worst offenders, though you should know that even harvest-friendly states may have some restrictions that you should be aware of. Make sure you do your homework, and don’t run afoul of the law!
Frequently Asked Questions
Not necessarily, and most smaller systems can be uninstalled and moved to a new location if required. The biggest “hang-ups” for removing an old system or transporting it elsewhere is that any major excavations or concrete work will necessarily have to be redone, while intricate modifications to existing gutters will need to be either repaired or the gutters replaced to ensure normal function.
No, you don’t have to. Some people build large dish or sail shaped catchers directly over their storage tanks for the same purpose, though they present much the same attendant issues as roofs, i.e., exposed to dust, dirt, animals and so on.
That depends completely on your handiness, the type of installation and any existing renovations or other preparations to your property that must be done. Generally, assuming you have all components on hand or scheduled for timely delivery a smaller “residential” system can be installed and operational in 2-3 weekends of work, and a simple rain barrel can be installed in an afternoon.
Big time: Although below ground tanks will generally not freeze when properly installed and sited, above ground tanks will freeze with the expected destructive results. Pipes will pull loose or crack, fittings will burst, and lids and overflows will swell or pop off. Not good. Above ground water tanks and barrels must be drained prior to the first hard freeze or you will face the consequences.
A rainwater collection system is no longer strictly in the domain of large scale crop irrigation for farmland.
Even tiny suburban and urban properties can make good use of harvested rainwater for a variety of purposes, and today more than ever before such systems are well within the grasp of a DIY prepper, both in affordability and accessibility.
A rainwater catching system can be adapted to virtually any structure, including residential and commercial properties, so if you’ve been putting off the setup of one of these systems you are officially without excuse.
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.