Collecting rainwater is one of the simplest and most reliable ways to build water independence for your home or homestead. As preppers know, water is the foundation of survival and in a grid-down scenario, wells and municipal systems may not be an option. By collecting rainwater and storing it safely, you create a renewable supply that can sustain your family, livestock, and garden even during extended droughts or emergencies.
Modern rainwater harvesting systems can range from basic DIY setups to advanced underground cisterns with filtration and pumping systems. With the right planning, you can collect thousands of gallons per year from your roof, more than enough to cover daily needs and irrigation. According to FEMA, households should store at least one gallon of water per person per day for emergencies, but with proper storage and treatment, your rainwater supply can go far beyond that minimum.
For those starting their prepping journey, investing in a rainwater collection system like the RTS Home Accents 50-Gallon Rain Barrel is a practical first step toward true self-reliance.
Why You Should Consider Collecting Rainwater
Collecting rainwater is not a new idea, in fact, it’s one of humanity’s oldest survival practices. Ancient civilizations used cisterns, clay pots, and carved stone systems to gather and store rainfall for everyday use. Today, this timeless method is making a comeback among preppers and homesteaders who recognize the value of having an independent water supply when municipal systems fail or wells run dry.
By collecting rainwater, you’re not only reducing your household’s reliance on treated municipal water but also cutting down on monthly utility costs. The collected water can be used for gardening, livestock, sanitation, and with proper filtration, even for drinking. According to the EPA’s WaterSense program, outdoor water use accounts for nearly 30% of total household consumption, making rainwater harvesting an effective way to conserve potable water and lower your environmental footprint.
Beyond conservation, rainwater collection is also a key preparedness measure. In a crisis, whether caused by drought, contamination, or infrastructure failure, a well-designed rainwater system can supply weeks or even months of clean water. Many folksbegin with a simple barrel setup like the durable Rain Wizard Urn, which blends functionality with a decorative look that fits any homestead.
In short, collecting rainwater empowers you to take control of your most vital resource, ensuring that no matter what happens, your family stays hydrated, your crops stay watered, and your preparedness plan remains rock solid.
Disadvantages of Collecting Rainwater to Know:
While collecting rainwater offers freedom and resilience, it also comes with challenges every prepper or homesteader should understand before setting up a system. One of the biggest concerns is contamination, since rainwater can pick up pollutants, bird droppings, or chemical residues from roofing materials. To prevent this, install a first-flush diverter and use food-grade collection barrels to ensure the cleanest possible water. For added safety, many preppers use a portable filtration unit like the Sawyer Squeeze Filtration System, which removes 99.99% of bacteria and protozoa directly from stored water.
Another issue is algae and mosquito growth. When sunlight hits standing water, algae thrive, and mosquitoes quickly follow. Using opaque containers, tight-fitting lids, and a small amount of bleach or chlorine-based treatment helps prevent growth. According to the Centers for Disease Control and Prevention (CDC), keeping storage containers sealed and treating water regularly is essential to stop mosquito breeding.
Finally, local rainwater collection laws can vary. Some states, such as Colorado, have regulations limiting how much rainwater can be stored or how it’s used. Always check your local water rights and building codes before installing large cisterns or underground tanks.
Despite these drawbacks, proper design and maintenance can minimize risks and make collecting rainwater a safe, sustainable practice for both emergency preparedness and everyday use.
What do you need to get started?
Before collecting rainwater, it’s crucial to understand how each part of your system works together, from the roof to the tank. A successful setup includes three main components: the catchment area, conveyance system, and storage. Your roof serves as the catchment area, so its material matters. Metal, tile, or asphalt shingles are fine for garden and cleaning use, but if you plan to drink the water, opt for a metal or coated roof that doesn’t leach chemicals.
The conveyance system, typically gutters and downspouts, channels rainwater from the roof to your collection point. Install leaf guards and mesh screens to trap debris and prevent clogs. Adding a first-flush diverter ensures that the first few gallons of dirty rainwater (containing roof dust and bird droppings) are discarded before the clean water reaches your tank.
Next, you’ll need a storage solution. For small-scale setups, rain barrels or plastic totes work well, but serious preppers often upgrade to underground or above-ground cisterns that can hold hundreds of gallons. A durable option for beginners is a Rain Barrel Diverter Kit, which includes everything needed to connect directly to a standard downspout.
Filtration and purification come next. A multi-stage filter or UV purifier can make stored rainwater potable, especially when paired with activated carbon filters to remove taste and odor. According to Ready.gov, households should keep at least a two-week emergency water supply, but collecting rainwater allows you to exceed that target easily.
Finally, routine maintenance is key: clean gutters twice a year, check for leaks, and inspect tanks for algae buildup. A well-maintained rainwater system not only reduces your dependence on public water but also ensures you’ll have a clean, renewable supply when others don’t.
How much water should I collect?
When collecting rainwater, the amount you should store depends on your household size, local rainfall, roof area, and usage goals. A family that only wants water for gardening will need far less than one relying on it for full-time off-grid living.
The simplest way to calculate your collection potential is by using this basic formula:
Gallons collected = Roof area (sq. ft.) × Rainfall (inches) × 0.623
That constant (0.623) represents how many gallons of water fall per square foot per inch of rain.
For example, if your roof measures 1,200 square feet and your area receives 30 inches of annual rainfall, you could harvest roughly 22,400 gallons per year. Of course, not every drop is captured, debris, evaporation, and overflow can reduce that by 10-20%. Still, even a modest system can produce thousands of gallons annually, enough for emergency use or irrigation.
As a preparedness rule, FEMA recommends for a family of four, a minimum of 120 gallons per month. Having a rainwater collection system ensures you can easily exceed this target and build a sustainable long-term reserve. To make calculations easier, many preppers rely on digital rain gauges like the AcuRite 00899 Wireless Rain Gauge, which tracks rainfall amounts automatically and helps determine how much water is entering your system.
Finally, consider expanding capacity gradually. Start with a 50- to 100-gallon barrel, then add more tanks or an underground cistern as your water needs grow. Proper planning ensures your rainwater system meets both your daily and emergency preparedness goals year-round.
Collecting Rainwater: Storage Options
When it comes to collecting rainwater, choosing the right storage system determines how safe, durable, and practical your setup will be. The best option depends on your available space, budget, and long-term water goals. From lightweight plastic tanks to massive underground cisterns, every material offers unique benefits and a few drawbacks.
For most preppers, the goal is to balance capacity, longevity, and water quality. A small backyard system might rely on a 50-gallon rain barrel, while an off-grid homestead could use a 5,000-gallon steel or concrete tank buried underground. According to the U.S. Environmental Protection Agency (EPA), properly maintained rainwater storage not only reduces stormwater runoff but also helps conserve potable water resources.
Below are the most common and reliable storage options for preppers who take collecting rainwater seriously.
Plastic Water Tanks
When it comes to collecting rainwater, plastic water tanks are often the go-to option for beginners and seasoned preppers alike. These tanks combine affordability, ease of installation, and long-term reliability, making them perfect for both suburban yards and off-grid homesteads. Constructed from high-density polyethylene (HDPE) or polypropylene, these tanks are lightweight yet remarkably tough, capable of withstanding harsh weather and UV exposure when properly treated.
Plastic tanks are available in a huge range of sizes, from compact 35-gallon barrels for garden use to massive 2,500-gallon cisterns for full-scale water storage. The key advantage of plastic is its cost-to-capacity ratio. You can build a reliable system for a fraction of what steel or concrete tanks would cost. Because plastic tanks are non-corrosive, they’re also ideal for collecting slightly acidic rainwater, which can cause metal tanks to degrade over time.
However, not all plastics are created equal. Always choose food-grade, BPA-free, and UV-stabilized materials to prevent chemicals from leaching into your water. Tanks labeled “NSF/ANSI 61 certified” meet safety standards for potable water use. For above-ground setups, position the tank on a level, reinforced base such as a concrete pad or gravel bed to prevent tipping or warping when full.
Sunlight is the main enemy of plastic tanks. Exposure encourages algae growth and degrades plastic over the years. To combat this, opt for opaque or dark-colored models and place them in shaded locations whenever possible. A great example is the Norwesco 35-Gallon Horizontal Water Tank, which features UV stabilization and a compact design perfect for tight spaces or small gardens.
For preppers living in colder climates, ensure the tank is equipped with an overflow valve and bottom drain, and consider adding insulation or a tank heater during freezing months. Plastic tanks also work well in modular systems — you can connect several with PVC pipes to scale your storage over time.
Routine maintenance is simple: flush the tank every six months, inspect fittings, and use a mild bleach solution to clean interior walls. A properly maintained plastic tank can last 10–20 years, providing a reliable, low-cost backbone for your rainwater harvesting system.
Whether you’re collecting rainwater for gardening, livestock, or emergency reserves, plastic tanks offer the perfect balance of affordability, simplicity, and expandability for any preparedness plan.
Steel Water Tanks
For serious preppers and off-grid homeowners committed to collecting rainwater long-term, steel water tanks are among the most durable and secure options available. Built from galvanized or stainless steel, these tanks can last decades when properly maintained, offering a rugged solution for large-scale water storage that easily withstands harsh weather and mechanical stress.
Steel tanks come in both corrugated and smooth-wall designs, ranging in size from 500 gallons to over 10,000 gallons. Their rigid structure allows them to hold immense water pressure without bulging or warping, a major advantage over plastic. Because steel is opaque, it naturally shields water from sunlight, slowing algae growth and reducing the need for chemical treatments.
To prevent corrosion, most tanks are hot-dip galvanized, meaning they’re coated inside and out with a layer of zinc that resists rust. For potable water storage, a food-grade liner or epoxy coating is strongly recommended. These liners not only preserve water quality but also make cleaning much easier.
Unlike plastic tanks, which can deform or crack over time, steel models excel in extreme conditions , whether under heavy snow loads, intense sunlight, or high winds. They’re also more resistant to animal damage, making them ideal for rural installations. However, due to their weight, steel tanks often require professional installation and a reinforced base. Once in place, they demand very little maintenance beyond periodic liner checks and external rust inspection.
According to Texas A&M AgriLife Extension, steel tanks are among the most reliable long-term options for rainwater harvesting systems, especially when combined with proper filtration and overflow management. They recommend positioning tanks downhill from the catchment area to take advantage of gravity-fed pressure, reducing the need for pumps.
For preppers building a resilient water system, investing in steel tanks is a long-term decision that pays dividends in peace of mind. They not only safeguard your water against light and contamination but also stand strong when lesser materials fail, a critical factor when self-reliance is the goal.
Wooden water tanks
For those who appreciate traditional craftsmanship and natural aesthetics, wooden water tanks offer a beautiful yet functional solution for collecting rainwater. While they may seem like a relic of the past, wooden tanks are still a viable choice today, especially for preppers who value renewable materials and old-world reliability. Historically, these tanks were made from redwood, cedar, or cypress, woods chosen for their natural resistance to decay and insects.
Modern wooden tanks function much like wooden barrels: the staves (vertical slats) are tightly bound by galvanized steel hoops that compress as the wood swells with water, forming a watertight seal. This self-sealing property is one of the most unique features of wood construction. When properly built and maintained, a quality wooden tank can last 20 to 30 years or more.
However, maintaining a wooden tank takes more effort than caring for plastic or steel systems. The tank must stay moist to prevent shrinkage and cracking, so it should never be left dry for long periods. Over time, the metal hoops may loosen and need to be retightened. To prevent leaks, most preppers line their tanks with a food-grade polyethylene liner or apply a non-toxic waterproof coating on the interior surface.
Temperature control is another advantage since wooden walls provide natural insulation, keeping stored rainwater cooler in summer and reducing the risk of freezing in winter. While wood isn’t ideal for large-scale underground systems, it’s excellent for aesthetic above-ground installations, especially in temperate climates. Wooden tanks fit seamlessly into garden landscapes or rustic homesteads, providing both beauty and practical storage.
For preppers interested in sustainable materials and traditional methods, wooden water tanks demonstrate that collecting rainwater doesn’t have to look industrial. With the right care and sealing, they can provide decades of dependable service and a timeless charm that blends utility with heritage.
Concrete block cistern
For preppers serious about collecting rainwater on a large scale, concrete block cisterns are one of the most durable and long-lasting storage solutions available. These heavy-duty systems have been used for centuries to store everything from drinking water to irrigation reserves, and when properly designed, they can last for decades with minimal upkeep.
Concrete cisterns can be built above or below ground, depending on your available space and climate. Above-ground tanks are easier to inspect and maintain, while underground installations offer better protection from sunlight, temperature fluctuations, and accidental damage. The thick concrete walls act as natural insulation, helping maintain stable water temperatures year-round, a huge advantage for preppers in both hot and cold climates.
Because concrete is porous, sealing is the key to longevity. Before use, the inside should be coated with a non-toxic, waterproof concrete sealant to prevent seepage and contamination. For DIY projects or repairs, many preppers rely on products like Quikrete Hydraulic Water-Stop Cement, which sets quickly and effectively seals cracks or joints under wet conditions. Proper sealing not only keeps your water clean but also prevents the growth of algae or bacteria within the pores of the concrete.
Another advantage of concrete cisterns is their strength and stability. They can withstand heavy soil pressure, animal interference, and even partial ground movement during floods or earthquakes. When paired with proper inlet filters and overflow controls, a concrete cistern becomes a nearly maintenance-free, high-capacity storage system capable of holding thousands of gallons.
According to the University of Arizona Cooperative Extension, concrete systems are among the most recommended for permanent homesteads and large-scale water catchment. Their research emphasizes regular inspection of seams and lids to ensure water quality and to prevent mosquito intrusion, a critical step for any long-term rainwater harvesting system.
Despite their higher upfront cost and the need for professional installation, concrete cisterns offer unmatched longevity, security, and water protection. For preppers seeking a near-permanent rainwater solution, this traditional approach delivers both reliability and peace of mind, ensuring that your collecting rainwater efforts remain safe and sustainable for decades to come.
Underground cisterns
When collecting rainwater on a large scale, many preppers choose to go underground, literally. Underground cisterns are the most discreet and secure way to store thousands of gallons of water while protecting it from light, heat, and freezing temperatures. Whether made from fiberglass, polyethylene, or concrete, these buried systems are designed for long-term use and minimal environmental exposure, making them ideal for serious off-grid homesteads or rural survival retreats.
One of the greatest advantages of an underground cistern is temperature regulation. Because the tank is buried, it maintains a naturally cool and stable temperature, drastically reducing algae growth and evaporation losses. This is especially beneficial in hot or arid regions where above-ground tanks suffer from constant UV exposure. The soil also acts as a natural insulator, preventing freezing in winter, a crucial factor for preppers living in northern climates.
Installation, however, requires careful planning and you’ll need to assess soil type, drainage, and access points to ensure proper placement. Tanks should rest on a compacted gravel base with side support to prevent collapse. Additionally, installing manhole covers, vent pipes, and overflow drains is essential for maintenance and safety. Many preppers also integrate a submersible pump system to move water to the surface for household or irrigation use. A dependable option is the Zoeller 1/2 HP Submersible Utility Pump, known for its reliability in both potable and non-potable systems.
Because underground tanks are out of sight, it’s important to schedule regular inspections at least twice a year. Check for settling, cracks, or leaks that could allow contaminants or groundwater infiltration. Filters should be cleaned after heavy rainfalls, and access hatches must be sealed tightly to keep insects and rodents out.
The capacity of underground cisterns can range from 1,000 to 10,000 gallons or more, depending on your available space and rainfall collection area. When paired with a roof catchment system and first-flush diverter, an underground cistern can support an entire household’s water needs for months, even in dry seasons.
For preppers who prioritize stealth, long-term security, and resilience, underground cisterns represent the pinnacle of rainwater storage. They protect your investment, shield your supply from environmental hazards, and provide a near-invisible backbone for your collecting rainwater system.
Rain Barrels
For beginners or those with limited space, rain barrels are the simplest and most affordable way to start collecting rainwater. These compact systems usually hold between 40 and 100 gallons and can be easily installed under a single downspout to capture runoff from your roof. Despite their modest capacity, they’re an excellent entry point for preppers who want hands-on experience with water harvesting before investing in larger cisterns or tanks.
Rain barrels can be made of plastic, wood, or metal, but plastic (especially high-density polyethylene) is the most common and cost-effective. When choosing one, look for a closed-lid design with a fine mesh or screen filter to prevent leaves, insects, and debris from contaminating your supply. Most preppers also add a spigot or hose attachment at the base to easily fill watering cans or connect multiple barrels in series. For example, the Impressions 50 Gallon Nantucket Rain Barrel blends elegant design with durable construction and comes equipped with an integrated planter on top, ideal for combining beauty and utility.
The placement of your rain barrel system makes a big difference. Choose a flat, stable surface, ideally elevated on a cinder block platform or wooden stand, to increase water pressure for gravity-fed flow. Keeping barrels shaded helps minimize algae growth, while using opaque materials reduces sunlight penetration. If you live in colder climates, remember to drain your barrels before freezing temperatures set in to avoid cracking.
Although rain barrel water isn’t typically safe for drinking without treatment, it’s perfectly suitable for gardening, lawn care, and sanitation. Adding a first-flush diverter and a simple carbon filter can further improve water clarity and reduce odor. For safe use, the U.S. Environmental Protection Agency (EPA) recommends cleaning your barrel at least once per season and inspecting downspouts regularly to prevent buildup of contaminants.
Over time, you can expand your setup by linking multiple barrels together, increasing capacity to several hundred gallons. Many preppers integrate rain barrels as part of a layered water security system, using them for day-to-day needs while storing purified water separately for emergencies.
In short, rain barrels are an easy first step toward collecting rainwater and building long-term water independence. They require minimal investment, little maintenance, and offer immediate results, all while helping you become more self-sufficient in your preparedness journey.
Conclusion
In the end, collecting rainwater isn’t just an eco-friendly hobby, it’s one of the most practical and empowering steps a prepper can take toward full water independence. Whether you start with a single 50-gallon barrel or invest in a full underground cistern, each drop you capture increases your resilience against droughts, grid failures, or supply chain disruptions.
The beauty of rainwater harvesting is its scalability. You can begin with a small DIY setup using gutter diverters and food-grade barrels, then gradually expand into a comprehensive system with filtration, pumping, and large-capacity storage tanks. For many homesteaders, it becomes a cornerstone of sustainable living, providing clean water for gardening, livestock, and even household use when properly filtered.
To simplify your setup, consider investing in an all-in-one starter kit such which includes everything needed to connect your roof runoff to a safe, sealed container. This kind of system offers immediate results and a solid foundation for expansion later.
Preparedness isn’t about fear, it’s about foresight. Water is life, and being able to source it directly from the sky is one of the oldest and most dependable survival strategies known to humankind. By maintaining your system, monitoring storage quality, and following proven safety practices, you can ensure a consistent water supply for years to come.
Start simple, think long-term, and remember that every drop stored today could make the difference tomorrow. With a well-designed system and a little effort, your home can become a self-sustaining sanctuary, ready for whatever the future brings.
Author Bio:
Bob Rodgers is a lifelong outdoorsman, herbalist, and seasoned prepper with over 20 years of real-world survival experience. As the founder of PreppersWill.com, he shares practical advice on self-reliance, off-grid living, and disaster preparedness, no hype, just hard-earned lessons from decades of hands-on prepping.
Last updated on: October 25, 2025
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