How to Harvest Rainwater: The Complete Guide

If you’re planning to move away from the city and start living off the grid, then harvesting rainwater is something you should seriously consider. It has a great potential to be your water source, and also it saves a lot of money on water expanses, as you can use it both indoors and outdoors. Harvesting rainwater can be done in the city and urban areas as well, as more and more states in the USA encourage citizens to collect rainwater for a personal use.

In this article, I will share with you everything you need to know about rainwater harvesting, how it can be done, how to treat and clean the water, the different uses of the water, legality issues, and more. I will even recommend about some great rainwater harvesting kits, so let’s get started and dive deeper into the topic at hand.

What is Rainwater Harvesting?

Rainwater harvesting is the process of collecting the runoff of the rain and then storing it for later use, both for indoor and outdoor needs. The most traditional way to harvest rainwater is by using the roof of the house. The rain collects in the gutters and then transfers the water to a storage device. This can be a barrel or other more advanced storage devices like a large cistern, all of which I will elaborate later in the article.

Rainwater harvesting is becoming more and more popular all over the world, and, as previously mentioned, many states in the USA encourage their citizens to do so. It’s an amazing alternative way for household water supply and the uses of the water are diverse: it can be used for farming, cleaning the house, washing the car, and even for drinking and consumption after it’s treated properly. These are only a few uses of the water, as I will mention a little more down the road. In countries like Australia and Germany, where green building movement is on the rise, rainwater harvesting is becoming a norm.

Harvesting rainwater means that you take control of the water supply and save a lot of money, and that you’re not dependant on urban infrastructure. The harvesting system can be designed and configured according to your needs and uses, both in the house and outdoors in the garden and landscape.

Is Rainwater Harvesting Legal?

Legality issues may differ from one country to another when talking about rainwater harvesting. In this section, I will cover the legal issues of rainwater harvesting in the main English speaking countries, but you should always check this issue no matter where in the world you are from, so you won’t break any laws or possible restrictions. Also, check out my article that explores is it illegal to collect rainwater.

Is Rainwater Harvesting Legal in USA?

In USA, The Federal Government has no laws or restrictions on this matter and most of the states in America allow and even encourage rainwater harvesting. These states offer their citizens with tax credit or exemption for equipment purchased for the purpose of rainwater harvesting. However, some states do have various restrictions on the amount of rainwater that one can collect as well as the method of collection.

The rationale behind these restrictions is the belief not to disrupt the natural flow of the rain water back into streams and different water bodies on the planet. With that said, a study that was made by the Scientific World Journal found that rainwater harvesting has almost no effect on the hydrological cycle and that this water used by the people finds its way back to Earth when they use it in their gardens, yards and so on.

To sum things up, it is not illegal to harvest rainwater in USA, but you should check with the specific state if the process is encouraged and comes with benefits, legal or legal with some restrictions to it.

Here is the list of the U.S. states with their laws and restrictions concerning rainwater harvesting:

  • Alabama – There are no regulations concerning rainwater harvesting and it is considered a private property right.
  • Alaska – In Alaska, rainwater harvesting is actually the primary water source for a lot of residents, so it is unrestricted here. However, there are regulations concerning groundwater harvesting and it can be purchased as a water right.
  • Arizona – Rainwater harvesting in Arizona is perfectly legal. According to House Bill 2830, cities and towns can also establish a fund if they choose to for the purpose of rainwater harvesting systems.
  • Arkansas – Rainwater harvesting is legal and allowed, but there are some restrictions to take into consideration. If the harvesting system is or was designed by a professional engineer licensed in the state of Arkansas, is or was designed using appropriate cross-connection safeguards, and it complies with the state’s Plumbing Code, then the harvested rainwater can be used for non-potable purposes.
  • California – In California, governmental, commercial and residential landowners are allowed to install, maintain and operate systems for the catchment of rainwater and that is for purposes that are specified.
  • Colorado – House Bill 16-1005 states that residents may collect rainwater in two barrels that have a combined capacity of 110 gallons. This collected water can then be used only on the property where it was collected from and only for outdoor purposes.
  • Connecticut – The state of Connecticut encourages its residents to collect rainwater, therefore there are no known restrictions as for rainwater harvesting.
  • Delaware – Delaware offers various incentives to its citizens to collect rainwater. Here too, there are no restrictions as for rainwater harvesting.
  • Florida – No restrictions, as the state encourages its residents to harvest rainwater. Some local municipalities in Florida offer tax incentives and rebate programs to residents who decide to harvest rainwater.
  • Georgia – Rainwater harvesting is allowed in Georgia only for outdoor use and purposes. Bear in mind that this restriction is extremely regulated there.
  • Hawaii – Rainwater harvesting is encouraged in Hawaii and there are no restrictions on this matter.
  • Idaho – Residents of Idaho may capture and collect rainwater as well as diffused surface water that is on their own property, only if it doesn’t injure or damage the existing water rights of other residents and that the rainwater hasn’t entered natural waterways.
  • Illinois – Plumbing-Rainwater systems Bill SB0038 states that rainwater that were collected can be used only for non-potable purposes and that the systems that harvest rainwater must be built according to the Illinois Plumbing Code.
  • Indiana – There are no regulations nor restrictions as for rainwater harvesting and the state of Indiana encourages its residents to harvest rainwater.
  • Iowa – There are no restrictions no regulations as for rainwater harvesting.
  • Kansas – Rainwater harvesting is allowed and legal in Kansas. There is no need for permits as long as the collected rainwater is being used for domestic purposes like watering the lawn and garden, watering livestock, household use and so on.
  • Kentucky – There are no restrictions nor regulations as for rainwater harvesting.
  • Louisiana – It is legal to collect rainwater. However, the state statutes require covers for large tanks (cisterns).
  • Maine – There are no restrictions nor regulations as for rainwater harvesting.
  • Maryland – There are no restrictions nor regulations as for rainwater harvesting. Some counties offer their residents incentives for harvesting rainwater.
  • Massachusetts – It is legal to harvest rainwater and the state of Massachusetts encourages its residents to do so.
  • Michigan – It is legal to harvest rainwater and also encouraged in the state of Michigan.
  • Minnesota – It is legal to harvest rainwater and encouraged in Minnesota.
  • Mississippi – It is legal to harvest rainwater.
  • Missouri – It is legal to harvest rainwater and the state of Missouri also encourages it.
  • Montana – It is legal to harvest rainwater and also encouraged here.
  • Nebraska – It is legal to harvest rainwater and a few universities even promote it.
  • Nevada – According to NB74, rainwater collection is allowed under the grant of a water right. Legislative Committee on Public Lands plans to review all water sources in the future, so stay tuned.
  • New Hampshire – It is legal and also encouraged to harvest rainwater.
  • New Jersey – It is legal to harvest rainwater in New Jersey. Assembly Bill 2442 requires that the Department of Environmental Protection establishes a Capture, Control, and Conserve Reward Rebate Program for residents who use eligible techniques for the purpose of rainwater harvesting on their own properties.
  • New Mexico – It is legal and also encouraged to harvest rainwater.
  • New York – Rainwater harvesting is legal, encouraged and even taught in the state of New York.
  • North Carolina – It is legal to harvest rainwater in North Carolina, however there are a few regulations on this matter. According to House Bill 609, the Department of Environment and Natural Resources will provide state-wide assistance and will also ensure best management practices for water reuse and the harvesting of rainwater. Also, the benefits of rainwater harvesting will be recognized by the Senate Bill 163 for future water supply of the state.
  • North Dakota – It is both legal and encouraged to harvest rainwater in North Dakota.
  • Ohio – It is legal to harvest rainwater in Ohio for both potable and non-potable purposes, as long as the system provides drinking water to no more than 25 people.
  • Oklahoma – It is legal to harvest rainwater in Oklahoma.
  • Oregon – It is legal to harvest rainwater in Oregon, but collection of rainwater can only be done using systems located on rooftops.
  • Pennsylvania – It is both legal and encouraged to harvest rainwater in Pennsylvania.
  • Rhode Island – It is legal to harvest rainwater and residents of Rhode Island enjoy various incentives as well, like a 10% tax credit for the installation of a cistern to both individuals and businesses.
  • South Carolina – It is both legal and encouraged to harvest rainwater in South Carolina.
  • South Dakota – It is legal to harvest rainwater in South Dakota.
  • Tennessee – It is legal to harvest rainwater in Tennessee, as the use and practices of green infrastructure is allowed (according to Senate Bill 2417/ House Bill 1850).
  • Texas – It is legal to harvest rainwater in Texas. However, there are some restrictions on the matter. According to House Bill 3391, the system that collects the rainwater has to be incorporated into the design of the house or building and also, one must inform the municipality with a written notice.
  • Utah – It is allowed to harvest rainwater as long as the person who harvested the water on the land is the owner of the land or is leasing it. Other regulations on the matter state that a person who is registered with the Division of Water Resources is allowed store up to 2,500 gallons of rainwater, whereas a person who is not registered is allowed to store up to 200 gallons of rainwater using no more than two containers (up to 100 gallons per container).
  • Vermont – It is legal to harvest rainwater in Vermont.
  • Virginia – Citizens who decide to install rainwater harvesting systems are rewarded with an income tax credit. The state of Virginia promotes the use of rainwater in order to help reduce consumption of fresh water, reduce the demand on water supply systems and also promote conservation.
  • Washington – It is legal to harvest rainwater and there is no need for permits on the matter.
  • West Virginia – It is legal to harvest rainwater in West Virginia.
  • Wisconsin – It is legal to harvest rainwater in Wisconsin.
  • Wyoming – It is legal to harvest rainwater in Wyoming.

Here are a few more words on rainwater harvesting’s legality in the USA:

Is Rainwater Harvesting Legal in Canada?

The answer is that rainwater harvesting is not illegal in Canada, and therefore is not considered to be a criminal offense. However, you should know that this practice is being regulated in Canada by codes and regulations, provincial by-laws as well as municipal by-laws, as provincial government and municipal bylaws determine the right to harvest and use the rainwater in Canada. According to The National Plumbing Code, there is permission to collect rainwater for non-potable uses like flushing the toilet and for outdoor irrigation throughout Canada.

Therefore, the laws and regulations regarding collection of rainwater differ in Canada from one province to another. There’s a lack of significant legislation, therefore, when designing and constructing a rainwater harvesting system, you should always follow the provincial codes and municipal bylaws. One should always check with the local authorities as for rainwater harvesting. Collection of rainwater for use and purposes that are not permitted may lead to fines. The same goes for rainwater harvesting systems that are or were built not according to the code.

  • Alberta – Alberta has rules and guidelines as for residential use of rainwater. In addition to the guidelines, there’s a handbook that provides broader and deeper understanding of the technical components of the guidelines.
  • British Columbia – Here the rainwater is treated as a common property and falls under the law of capture. Therefore, rainwater doesn’t belong to anyone until it is captured. The right of landowners to harvest rainwater is unrestricted and not subject to concerns of downstream water users.
  • Ontario – In Ontario, there is permission to use rainwater for the purposes of toilet flushing, urinals, irrigation systems that are below ground or sub-surface. The Ontario Guidelines for Residential Rainwater Harvesting Systems lists a number of standards and regulations as for catchments, conveyance networks, and storage containers. Water must be properly controlled using draining and temperature controls, especially during winter when there is a probability of freezing, due to temperatures drop below zero.

Is Rainwater Harvesting Legal in the UK?

In the UK, it is perfectly legal and even encouraged to harvest rainwater by most water companies, especially in areas like the south eastern counties where the amount of rain is significantly less than along the west coast. With that said, there are still some standards and regulations that apply for collection of rainwater, especially if a cross-connection is made to the mains water supply. The supply of water for consumption and general health and safety are also regulated in the UK.

Here are some regulations you should know about:

  • Water Regulations Advisory Scheme (WRAS) – This regulates all aspects of mains water supplies. This includes valve types as well as fittings which interact with mains water. The most important thing to know here, is that any connection that is made from the mains supply to a rainwater harvesting system must have a physical air gap. This comes in order to prevent risk of non-potable water being siphoned back in to the mains supply.
  • Rainwater Harvesting Systems (BS 8515:2009) – The ration behind this code is to achieve consistent risk management, quality of water, installation standards, testing and regular maintenance of the systems that harvest the rainwater. It lists guidelines for suppliers to ensure that everything is maintained in high standards of excellence.
  • Planning Permission – Generally, planning permission for rainwater harvesting systems is not required, as they are considered a rainwater recycling system. Still, I do advice that you check with the relevant planning office just to be on the safe side.
  • Pipe Marking – Rainwater that was harvested must be labelled as non-potable, and therefore not suitable or used for drinking and consumption. Pipes that convey rainwater, no matter if below ground or within a property must be identified as such. The same goes for valves, outlets and other devices and appliances, as they must be labelled or tagged in accordance with WRAS Guideline IGN 9-02-5.
  • BRE Environmental Assessment Method (BREEAM) – This is less in the legality department and more of a recognised assessment method that applies to sustainable construction of commercial properties.

Is Rainwater Harvesting Legal in Australia?

Rainwater harvesting in Australia is legal and encouraged by the country. In fact, 26% of the houses in Australia have a rainwater tank, and outside of urban areas rainwater provides 63% of residential water, which is 109 billion litres. With that said, rules and regulations differ in various parts of Australia, as I will now list a few of them:

  • Victoria – As of July 2005, new apartments as well as houses must be built according to the requirements of 5 star standards regarding energy efficiency and water management. This means that building fabric must have a rating of 5 Star energy efficiency, the taps and fittings must be water efficient, and there needs to be either a rainwater tank for toilet flushing, or a solar hot water system.
  • Sydney and New South Wales – Here, the BASIX (Building And Sustainability Index) regulations demand the main water usage to be reduced by 40 percent. Any building design can meet this demand by including taps, toilets and showerheads rated 3A at least, and/or getting a rainwater tank that can be used for outdoor needs, flushing and laundry. By installing these, one can achieve the required water conservation.
  • South Australia – In South Australia, new homes are required to have a rainwater tank that is plumbed into the house.
  • Queensland – In Queensland, you can receive a rebate of up to $1,500 for purchasing and installing a home rainwater storage that the State of Queens in Australia has offered.
  • Gold Coast – In Gold Coast, it is mandatory to construct a 3,000-litre (800-gallon) rainwater tank in the Pimpama Coomera Master Plan area of Gold Coast. This is true for all homes as well as businesses centres that are connected to the Class A+ recycled Water system. You should also plumb or connect the rainwater tank to the outdoor faucets as well as to the cold-water washing machine.

What Are the Benefits of Rainwater Harvesting?

I’ve already mentioned some of the benefits, but here is the complete list of all the benefits and advantages of collecting rainwater, storing it and then using it for various purposes. So, let’s list all the benefits, shall we?

  • Harvesting rainwater helps to conserve water.
  • You’re self-sufficient and don’t depend on anyone for your water supply (great for off-grid living or living in cities where there are restrictions on water use).
  • You save a lot of money on water expanses.
  • Rainwater is clean (relatively) and free.
  • Rainwater is not chlorinated which makes it better for plants and garden use.
  • You can use rainwater as your primary water source or treat it as a backup source for emergencies.
  • A big storm can leave behind a runoff that damages the ground. Collecting rainwater can take care of excessive runoff.
  • The technologies for rainwater harvesting are simple, inexpensive and easily maintained.
  • Not only you enjoy free water, but it can also solve problems of drainage on your property.
  • The system can be built during construction of a new home or easily retrofitted to an existed home.
  • The system is extremely flexible which means that you can expand, reconfigure and even relocate it if needed.

What Can I Use Rainwater For?

Basically, anywhere tap water is used, so can rainwater be used, it’s as simple as that. Rainwater can be used for irrigation, indoors (without potable use) or for the entire house (including potable use). This is the big picture. Now, let’s get to specifics and see how exactly rainwater can be used inside and outside of the house:

  • Consumption/drinking (after properly treating and filtering the water)
  • Use it in toilets and for washing clothes
  • Washing the car
  • Washing your pet
  • Watering your garden and lawn (by hand or by connecting the rainwater system to a sprinkler system/irrigation)
  • Refilling fish ponds and fountains
  • Refilling a swimming pool
  • Washing the sidewalks and driveways

What Are the Best Ways to Collect Rainwater?

In this section, I will list three methods which are used to collect rainwater. The difference between the systems is their scale, as in principal, they are all designed to do the same thing, and that is to collect the rainwater and store it. Now, let’s learn how to collect rainwater using barrel, the “dry” system and the “wet” system:

  • Collecting rainwater using barrels – This is the easiest and most common way to collect rainwater. All you need to do is install a barrel at the gutter downspout and collect the rainwater. This barrel can be new or recycled. The advantages of this system are that it can be implemented easily and by anyone, no matter where you live. You don’t need to spend a lot of money on installation of a large or complicated system. The barrels don’t use a lot of space. As for disadvantages, the rainwater you can collect is limited (50-100 gallons), and it can easily overflow and thus waste water you could have collected.
  • The “dry” system – This system is similar to rainwater collection using a barrel, only here you use a much larger storage device. After each rain, the water collection pipe “dries” the rainwater from the roof directly into the storage device (from the roof and to the top of the tank). The advantages of this system are the ability to store a large amount of water. It is ideal in climates and areas where rainfall is infrequent and happens with large storm events. It’s not expensive to install the system, and because the system is not complicated, therefore it’s easily maintained. As for the primary disadvantage of this system, the storage device and tank must be located near the house.
  • The “wet” system – Using this system, the rainwater collection device or tank can be located away or farther from the house. Here, you install the pipes that collect the water underground to connect several or multiple downspouts from different gutters. The rainwater then fills the pipes underground, and then rise the vertical pipes to be transferred into the tank. Advantages of this system include the ability to collect rainwater from the entire surface and not just a specific spot of the roof. You can collect rainwater from multiple downspouts and gutters and you can also locate the big storage tank away from the house. The disadvantages are that this system is more expensive than the other systems, as you must install underground piping and maybe even apply pressure to lead the water into the tank (depending on the terrain and landscape). Also, gutters and tank inlet should differ from each other.

Here is a detailed demonstration of collecting rainwater with barrels:

How Much Rainwater Can You Collect?

There’s actually a simple formula to help you calculate exactly the amount of rainwater that you can collect according to your living area and roof size.

The formula: annual average rainfall in your area x square footage of your collection surface (roof) = total rainwater collection potential (gallons).

Use the following map to find out the annual average rainfall in your area:

Is It Safe to Drink Rainwater?

According to the CDC (Centers for Disease Control and Prevention), rainwater is not safe to drink, as it’s not as pure as you may think it is. You see, the rain that hits the roof and collection surface can wash with it various contaminants into the barrel or water tank. These contaminants may be bird poop or any other dirt that is present on the collection surface or the roof.

Even smoke and dust in the air can be dissolved in rainwater before it hits the roof. More than that, rainwater can carry with it viruses, bacteria, parasites and even chemicals that can lead to sickness and risk your health. Moving on, when the rainwater travels through the gutters, piping or even when it ends in the tank or barrel, the water can wash with it harmful chemicals like copper, lead and asbestos, not to mention dirt and germs.

Now, with all that said, it does not mean that you can’t use the rainwater for drinking. What you have to do is treat them properly, filter and purify them. Filtration removes debris from the water while purification or disinfection which is the next step, removes harmful substances and kills contaminants.

How to Filter and Disinfect Rainwater?

Today, many or almost all rainwater harvesting systems come with filtration tools and devices that are installed in the system. By using filters and screens, you’re not only ensuring that the water is cleaner, but also greatly reducing the need for maintenance of the system and allowing it to work for a longer period of time, with the piping and the entire system being cleaner.

Still, no matter how good the screens and filters are, particulates may find their way to the tank. So, in order to keep sediment at the bottom of the tank and not risk the rest of the water, you should always put the rainwater through screening, allow the sediment to settle without being disturbed, and also don’t use the water from near to the tank’s bottom. Instead you should place a floating filter, since it doesn’t disturb the sediment as it pulls the water from the tank’s middle.


Most of the systems use multiple filters. When considering filtration systems and devices, National Sanitation Foundation/American National Standards Institutions (NSF/ANSI) standards are the best and most stringent in the industry. The most important thing to know is that there are two highly important containment removal standards: Standard 53, “Drinking Water Treatment Units – Health Effects”, and Standard 42, “Drinking Water Treatment Units – Aesthetic Effects”. Standard 42 covers contaminants like chlorine taste and odor, and visible particulates, while standard 53 covers health-related contaminants, like lead, Cryptosporidium, Giardia, and volatile organic chemicals that may be in the drinking water. Systems that meet both 42 and 53 standards are expensive, but are considered to be safest and best to own.

The first filters in a system are cartridge filters. Their rating is determined by the size of the tiniest particle they can filter. Smallest numbers correlate to better filtration. Keep in mind, though, that finer filters are also pricier and work slower. Remember to change the filters regularly. For wells as well as to rainwater harvesting systems, you will need a larger (e.g., a 50 micron) filter or equivalent screen (e.g., 300 mesh). This is used in order to eliminate large particles as well as sand. It is best that this screen is accessed easily, as you’ll need to clean it every 3 months. Next you have another filter (20 or 10 micron filter), which is followed immediately by a 10 or 5 micron filter. You don’t have to clean these filters so often as the previous ones, so cleaning them once a year is enough.


In order to ensure that rainwater is safe for drinking, disinfection is a must, and that is the next step after filtration. In public water systems, disinfectants are added in order to destroy different microorganisms that may cause illness and disease both in people and animals. The same is required for rainwater.

Disinfection can be done using the following methods.


Chlorine has been disinfecting public water for centuries, eliminating waterborne diseases like cholera, dysentery, hepatitis and typhoid. In order to disinfect the water, you need to add 2.3 fluid ounces of household bleach per 1,000 gallons of water. The dosage rate will vary depending on the quantity, PH and temperature of the water that you want to disinfect and treat.

The downside of using chlorine to disinfect the water is that it might cause the appearance of such dangerous trihalomethanes (THMs) as the chloroform by simply combining with some natural organic material. Such a material can be a fulvic or humic acid, and these are frequently present in water. Because of that, it is crucial to keep the correct dosage rate when using this method. As for the smell and taste of the Chlorine, it can be removed using an activated carbon filter, also known as a charcoal filter. Filters with activated carbons are frequently produces from coconut shells, thus they are actually an ecologically green product.

Ultraviolet Light

For nearly 100 years, ultraviolet lights have been used in Europe and these days are becoming a common use in the US as well. When using UV lights as the disinfection method, the water must pass first through filters. If you don’t use filters first, you risk bacteria and pathogens to cast shadows in the flowing water and basically, you allow different organisms to find their way to the water.

The way that the UV lights work is that it penetrates the cell walls of the organism and thus disrupt the genetic makeup of the cell. This makes it impossible for the organism to reproduce, leaving it harmless. The UV lights don’t damage or harm the water as it doesn’t change the chemical composition of the water and doesn’t leave any by-products as well.

In order for the process and the disinfection to be 100% effective, you must use the right dose of UV light to a specific unit of water. Also, the water must be clear of various particulates like suspended solids.

There are several things to remember when using a UV light:

  1. You should replace the bulb according to the manufacturer’s instructions (after 9,000 hours or approximately every year).
  2. Because UV light is not visible to the human eye, it may seem as if it is lit, but in fact it not and so is not working.
  3. You should occasionally clean the glass that encloses the light in order for the UV light to be effective.
  4. If you don’t install a backup light, then the water needs to be shut off upstream of the bulb before you replace the unit. It is recommended to shut down the system first and then disinfect the water downstream.
  5. Each UV unit comes with its own flow rate, and it absolutely must match the water’s flow rate.
  6. You should install the UV light unit after you’ve cleaned all the filters, resulting in clean water that is free of bugs and ready to use.

To make things simpler and more convenient, you can purchase a unit that cleans the bulb automatically. This will greatly reduce maintenance requirements.

Membrane Filtration

This method pushes water through a layer of material. Technologies of pressure-driven membrane include microfiltration, ultrafiltration, nanofiltration and reverse osmosis. It is able to remove pharmaceuticals and there are no byproducts left after the process is finished.

  1. Microfiltration (MF) – This is a membrane separation process that uses a pore size of .03 to 10 microns. The smaller the pore size, the more the system will remove. These membranes remove of silt, sand, algae, clay, cysts and some bacteria.
  2. Ultrafiltration (UF) – In this method, the separation process is done by a pore size of approximately .002 to .1 microns. UF is able to remove anything that that the MF system removes, and even some viruses.
  3. Nanofiltration membranes (NF) – These membranes have an approximate pore size of only .001 microns. Because the pore sizes are small, they require much more power in order to push water through the membrane. This causes for more waste that is generated as opposed to the MF or UF systems. NF systems eliminate virtually all bacteria, viruses, cysts and other materials, including minerals.
  4. Reverse Osmosis (RO) – When talking about membrane technology, RO is the most widely used today. RO is able to remove particles as little as .001 microns, including natural organics, radium, cysts, bacteria, pesticides and viruses. It is recommended to look for a unit that is certified by NSF for contaminant reduction and not just safety. Also, you should know that these systems tend to produce waste water that has to be processed. The good news, is that units that are newer are becoming “greener,” and thus produce less waste. The waste can be removed by including plumbing through a greywater system to the irrigation system or directly to the septic system. A whole-house unit can cost $8,000 or more (this depends on the size of your house and family/water usage). You should perform maintenance on a regular basis to ensure clean and safe water. The most important thing to do is to change cartridges.


This method separates the water from the impurities by heating and then collecting the condensation. Because the process is very intense, there is a loss of about 5%-10% of the water because of evaporation. Distillation can remove almost all substances from the water except of volatile organic chemicals (VOCs) that evaporate easily. Some distillation systems come with carbon filters that remove the VOCs.

The process of distillation is slow in order to reduce energy requirements and similar to RO systems, it stores the purified water in a tank for future use. Distillation systems use a lot of electricity and also generate heat. Units that produce 5 -12 gallons of water per day will cost approximately $1,500 – $2,000. Automatic home units that are considered to be high-end (come with larger capacity for water storage) may cost even $4,000 or more.

Tip: Before you invest money in filtration and/or purification equipment, invest in removing particulates before they find their way into the system. Install roof washers, gutter screens and leaf screens. Remember, it’s a lot easier to remove materials before they enter the system than dealing and removing them after they are already inside the system.

The Recommended Household Use of Rainwater

When talking about using rainwater in off grid living, here is the best household practice to follow:

  1. Filter all the incoming and collected rainwater and store it in a small pressure tank.
  2. From this tank, the water splits into two paths: One for potable and the other for non-potable water.
  3. Add a purification method/system in order to produce potable water.

The advantage of this method is that you don’t need a big tank and the costs are way smaller, because you deal with less amount of water then a whole-house unit. On the other hand, there is a down side to this method as well, because it requires a dual plumbing system. One supplies filtered yet non-potable water for washing the clothes, using the toilet, irrigation faucets and more, while the other supplies potable water to the house faucets.

How to Maintain Rainwater Harvesting Systems

Because you’re the owner of the rainwater harvesting system, it is your responsibility to maintain it. Remember, that constant and correct maintenance won’t only ensure high quality water, but even prolong the system’s lifetime. When maintained properly, the rainwater is safe to be used both indoors and outdoors for all the uses I’ve mentioned earlier in this article.

I’ve talked about maintenance during the filtration and disinfection section, so here are a few tips:

  • Always clean and replace the filters and disinfection devices when required and according to the manufacturer’s instructions.
  • Regularly clean and inspect gutters and catchments to reduce the chance of contamination.
  • Do not mix water from other sources in the tank where you store the rainwater.
  • Clean the rooftop and catchment area just before monsoon or heavy rain and thunderstorms arrive.
  • Cover the roof outlet on the terrace with a mesh. This will prevent leafs and other solid debris from entering the system.
  • Open the diversion valve for the first 5-10 minutes of rain in order to dispose of the first flush which is polluted.

Recommended Rainwater Harvesting Kits and Barrels

Lastly, I want to recommend a few rainwater harvesting kits and barrels for you to try. Sure, this is not a whole, professional system, but it’s a start before moving on to the serious systems. Bear in mind that because these barrels don’t contain filters or disinfection devices, the water that is stored in them can’t be used for drinking. All recommended items are linked to their Amazon pages, where you can compare prices and read more reviews.

RTS Home Accents 50-Gallon ECO Rain Water Collection Barrel

This rain barrel is made of 100% recycled plastic and can store and provide up to 50 gallons of water. The back of the barrel is flat so you can put it against the wall and thus increase collection of water from the roof. The barrel also features plastic screen that keep out debris and insects from getting inside, a plastic Spigot shut off valve to connect a hose, and a front side overflow to keep the water from flooding against the outside wall.

  • Dimensions: 24” x 19” x 34”
  • Weight: 18 pounds
  • Capacity: 50 gallons

Click here to compare prices and read more reviews


COMMYEE 132GL Foldable Rain Barrel

A foldable rain bucket made of PVC material that is extremely durable, prevents pollution and sundries from entering the bucket and resistant to UV rays. Can store up to 132 gallons of water and when you don’t need to use it, simply fold and store it away. Features 8 PVC rods for complete support, 2 faucets with switch for an external water pipe, watering the garden and more, and 1 overflow port that discharges excess water and to connect to another rainwater collector if needed.

  • Dimensions: 37.8” x 6.7” x 6”
  • Weight: 10.08 pounds
  • Capacity: 132 gallons

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LIVINGPAL 100 Gallon Foldable Rain Barrel

Another foldable rain barrel that sets up in 5 minutes and when not needed, simply fold and store it away. Made of high-quality 500D PVC mesh fabric that is also anti-corrosion and can store up to 100 gallons of water. The top mesh keeps away insects and leafs from entering the barrel and contaminating the water. The barrel features 6 PVC support rods, 1 outflow valve and 2 spigots, so you can also connect it to other barrels in case there’s a need for additional water.

  • Dimensions: 38.75” x 6” x 5.5”
  • Weight: 8.8 pounds
  • Capacity: 100 gallons

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Final Words

There you have it, the most complete guide for rainwater harvesting. I hope I was able to clear every possible question and aspect of this endeavor. Harvesting rainwater can be an important part of your off grid life. It’s a unique and maybe somewhat challenging way to supply water to your household, but it’s worth every effort.

There are other important sides to living off the grid that you need to be aware of. How to prepare for off grid living, how to find the best portable solar panels and how to get connected to the off-grid Internet are among the highly significant topics covered by this blog. Feel free to browse the blog for more essential information. And above all, good luck in your new off grid life!

Alex Rejba

Alex is a seasoned survivalist, with a passion to all things related to prepping, hiking and living off the grid.

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