Rain Water Harvesting for Beginners

Rain Water Harvesting for Beginners

Rain Water Harvesting for Beginners

Updated on 10/1/2023
Emma DowneyBy Emma Downey
Gardening Expert
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Rain water harvesting is collecting and storing rain for reuse, as opposed to allowing rainwater to flow off and be absorbed into the ground or routed into drains, streams, or rivers. The goal of rainwater harvesting is to reduce the amount of water lost to runoff and In order to maximise water reuse, we must increase its supply. Because of this, who can reuse the water on several occasions? One of the simplest methods to reduce household water use and save money is to install a rain barrel, it will help you save money on your water bills. Rainwater collection is an intelligent and environmentally responsible choice, whether you choose to do it with a complex system built expressly for your needs or a simple design that uses rain barrels. You'll be doing well for the planet whether you do this or that.

As the effects of the climate crisis deepen and more regions of the world experience drier and more prolonged droughts, depletion of groundwater resources, and contamination of freshwater supplies due to seawater inundation, the practice of collecting rainwater is acquiring new relevance. 

Rain Water Harvesting for Beginners

Rain Water Harvesting for Beginners

The collection of rainwater can provide a source of potable water that is not tainted by pollution or other contaminants in regions of the world where water is either in short supply or is only accessible during certain times of the year. This type of water is known as "rainwater harvesting," Who can do it in areas where water is either in short supply or is only accessible during certain times of the year. Additionally, conserving rainwater can be a more affordable option for ensuring the supply of potable and hygienic water for use in the house and garden, as well as for use in agriculture and the care of animals that need to be hydrated than desalination or piping water across large distances. That is because desalination and piping water over long distances are both methods that require water to be piped over long distances. That is because desalination and piping water over long distances are both methods that require water to be piped over long distances.

Even though there are many different kinds of cutting-edge equipment available today for collecting rainwater, collecting rainwater stretches back thousands and even tens of thousands of years. An understanding of how to manage and store water is regarded by anthropologists to have been vital to the development of agriculture, particularly in climates with a lower average precipitation level. That is particularly the case in environments where there is less rainfall overall. 

rain water harvesting

rain water harvesting

Cisterns dating back to the Neolithic period have been unearthed in towns worldwide. These cisterns were used to collect and store precipitation. Around 2500 B.C., they discovered the territory now Israel and on the island of Crete, a part of Greece. Both of these locations are in the Middle East. Later, they were found in Venice, the Roman Empire, and Istanbul, among other places.

How Much Water Can You Save By Rain Water  Harvesting ?

The following equation is utilized by the Federal Energy Management Program to arrive at an accurate estimate of the total volume of water collected by rainwater harvesting systems:
The catchment area is calculated by multiplying the monthly rainfall in inches by the conversion factor (0.62) and then adding the collection factor (75 percent -90 percent to account for losses in the system)

How To Build A Rainwater Collection System

For instance, the NOAA's Climate Report indicates that the average amount of rain that fell each month over the contiguous United States in 2019 was slightly less than 3 inches. Using this amount and assuming a collection factor of 75 percent, the total water catchment for a roof with a surface area of 1,000 square feet would be:

1,000 x 3 x 0.62 x 75 percent = 1,395 gallons every month, or 16,740 gallons on an annual basis (minimum)

The Process: Capture, Store, And Reuse

Even the most basic rainwater harvesting systems require a place to collect the rain (which might be as simple as a roof), a mechanism to route the water (such as gutters and downspouts), and a place to store the water (like a barrel). Due to the lack of filtration and proper storage, the water collected by such a rudimentary system is only fit for the most basic of uses, such as watering a garden, putting out fires, or being used as grey water, which includes water used in toilet bowls.

A more complicated system would include a collecting system in addition to many layers of filters, This would prevent particles such as dirt and trash from entering the water supply. That would make the system more complex but would also provide more potential applications for the water. A suitable storage tank should include a mechanism to securely handle overflow water and be created elements that will not dissolve into the water and will prevent the formation of bacteria. Additionally, the tank should be constructed using materials that won't leach into the water. After that, the water storage tank needs to be hooked up to either a control system that can further filter the water to make it drinkable or, at the very least, a monitor that can tell the water's current purity level. In the end, the system would need a pump to direct the water, a flow meter, and a backflow prevention system, all of which would need to be connected to a power source.

Recycling used water versus collecting rainwater as a source of drinking water.

Rainwater Harvesting | Collect & Store The Cleanest Rain Water From Your Roof

It is not the same thing to collect rainwater as it is to recycle used water, so don't get them confused. However, the former can be included in the latter as part of a more extensive system. Because "grey water" is defined by what it is not, "grey water" refers to any wastewater from a household that does not come from the toilet. The water from the kitchen and bathroom sinks, the water from the shower or bathtub, the washing machine, and the dishwasher all go down the drain. Compared to water from the toilet, it contains fewer potential disease-causing organisms, also known as pathogens. As a direct consequence of this, disinfecting this water so that it can be reused is a lot less difficult.

Recycling grey water on-site in a home, apartment complex, workplace, or hotel is possible. The water can then be utilized for flushing toilets (at which point it is referred to as black water), watering gardens or lawns, or cultivating crops. When planning the layout of a rainwater collection system, it is common practice to incorporate grey water reuse to stretch the available captured water over a more extended period due to the water's ability to be reused for several purposes. For instance, collected rainwater may be filtered and stored before being used in an appliance like a washing machine or shower. The "grey water" that results from these activities could then be collected and put to use in irrigating the garden.

In regions where there is a dearth of sewage treatment facilities, the use of grey water can help cut down on the amount of wastewater that needs to be gathered and treated.

The Benefits That Never Stop Coming

Rainwater harvesting offers a variety of advantages in addition to lowering the demand placed on the freshwater resources in the area. Collecting rainwater during a storm can reduce the amount of runoff, which can cause local sewage systems to become overwhelmed and lead to contaminants from the surrounding area making their way to rivers, streams, lakes, and lakes ponds, and eventually the ocean.

Rainwater collection has several benefits, including preventing flooding in low-lying places and erosion in particularly arid environments, which are both commonplace.

rain water harvesting

rain water harvesting

If you acquire your water from a municipal source and pay for it, collecting rainwater can help you reduce the amount that you have to pay for it on a monthly basis.

The benefits of utilizing this technology have been acknowledged in many locations worldwide, which either mandate or actively push the installation of rainwater collection systems as a viable solution to water shortages. For instance, Bermuda, the United States Virgin Islands, and Santa Fe, New Mexico, have recently passed legislation requiring a rain catchment system to be installed on all newly constructed homes. Additionally, Texas now provides a tax exemption for purchasing harvesting systems to encourage residents to engage in the practice. Rainwater harvesting is practiced on a wide scale in several cities across the world, including Australia, Kenya, China, Brazil, and Thailand. 

How to HARVEST RAINWATER from your roof

Additionally, the Frankfurt Airport in Germany gathers rainwater for use in the landscaping and restrooms of its terminal.

Applications for Rainwater That Has Been Collected

Rainwater collected can be utilized virtually in the same way as water from a well, or who can use some other supply. Filtration of the water is an essential step to enhance its flavor and eliminate pathogens, grit, and other particles before who may use it for drinking (potable), preparing food, or any other activity involving direct human consumption. At the very least, it must be boiled at a rolling boil for at least one minute to eliminate any pathogens that could cause illness.

how to build rain water harvest

how to build rain water harvest

Outdoor Uses

  • The creation of gardens and landscapes
  • Swimming pools
  • Drinking water for animals
  • Duties around the house, such as washing the car or the dog, for example
  • Decorative water features such as bird baths or fountains
  • Putting out fires or providing emergency water

Indoor Uses

  • Washing machine
  • Dishwasher
  • A steam bath, a shower, or a hot tub
  • Toilet Utility sink

How to Harvest Rainwater

There are many ways to collect rainwater, ranging from easy do-it-yourself projects to more complex and sophisticated systems. What are your intentions concerning the water? That is the first and most important question that needs to be addressed. Because of this, the required amount of filtration and monitoring, as well as the level of complexity and cost that your system will require, will be determined.

water flowing

water flowing

A straightforward system that collects rainwater from a roof via downspouts and stores it in a barrel or tank is an attractive option for use in the garden. Who can do this to water plants or carry out a variety of other activities that take place outside? The majority of the maintenance that is required for these systems to function well consists of routine cleanings of the gutters.

The water adds additional complexity to a home, including the water used in the kitchen, bathroom, and laundry room (or outdoors for a swimming pool). Because of this, the water you collect will need to be filtered through at least one respectable primary filter before it can be used (and those filters should be monitored and changed regularly). You will need a pump to transport the water to where it is necessary, and who should store the water in a cistern resistant to germs. 

The cistern can be buried or kept above ground, depending on your preference. This water will need to be utilized frequently; otherwise, bacteria will start to flourish in it. When something is not used for a long period of time, it can start to lose its length of time unless it is treated chemically or in some other way. If your roof serves as the collecting area, you will want to take precautions to imperative that you take precautions to prevent any lead from coming into touch with the water, heavy metals, or wood that has been preserved chemically.

is harvesting rain

is harvesting rain

Slate, aluminum, and galvanized iron are the three types of roofing materials best suited for usage on structures designed to collect rainwater. Other suitable options include zinc and copper. In the end, you will need to install plumbing inside of your house for the rainwater you have gathered to be delivered to the various appliances and faucets in your home where you will utilize it. Pricing for each of these items shifts significantly based on the kind of plumbing that is already installed.

System For Drinkable Water

Turning collected rainwater into water that those who can use for drinking, also known as potable water, is the most challenging aspect of any rainwater collecting system. These systems would incur all of the previously mentioned costs, including selecting a secure location for collection, filtration, secure storage, pumping, and additional filtering or treatment, in addition to other piping and pumps. Who would incur all of these costs in addition to the mentioned costs?



The filtration for this kind of system can cost up to $20,000 and requires considerable maintenance and attention. This is due to the fact that if you forget to change the filter, the quality of the water you drink could be compromised, which could result in serious illness or even death. On the other hand, making this investment can make it possible for your house or building to support its needs. If there is sufficient rainfall in your area, likely,You won't have to dig a well or be hooked up to a water supply from the city because neither of those things are required. That could be an alternative that helps you save money.

A growing number of companies and professionals can work with you on any of the systems above and ensure that you are getting the combination of filters, storage, monitors, pumps, and pipes that you require for your location and the water requirements that you have. These businesses and professionals can work with you on any of the systems above. These professions and companies can be discovered online and in businesses located in their respective communities.

When it comes to ensuring that the water inside of your home is safe, it is in your best interest to seek the guidance of a trained professional. Doing so is in your best interest particularly the water that will be consumed, even if you want to work putting the system together on your own. It is in your best advantage to seek the direction of a skilled professional even if you intend to complete the job on your own. This is true even if you intend to complete the work on your own.

Frequently Asked Questions

To Collect Rainwater, What Size Water Tank Do You Need To Use?

The Environmental Protection Agency estimates that the typical drum found in a household is capable of holding 55 gallons of liquid.

For the sake of comparison, the typical domestic consumption of water by an American is 82 gallons per day.

rain tank

rain tank

If you want to utilize the collected rainwater as a supplement to your primary water source, you may get by with a much smaller number of rain barrels than you might think. However, if this is the only water supply you have, you should look into purchasing a vast tank. Tanks with capacities ranging from 600 to 50,000 gallons are readily accessible.

What Are The Financial Considerations Involved In Collecting Rainwater?

The cost of installing a residential rainwater harvesting system can range anywhere from $3,000 to $20,000, depending on whether you want just a few barrels or an entirely off-grid, filtered water source. The cost will be lower if you wish to only a few barrels.

How Does The Standard Tap Water Stack Up Against The Water That Comes From The Rain?

The chlorine and other chemicals added to treated tap water effectively remove harmful microorganisms such as viruses, germs, and parasites. 



However, it is also possible for it to contain a wide variety of contaminates, some examples of which are aluminum, lead, arsenic, and mercury. Rainwater, which does not include harmful pollutants, is gentler and purer than other types of water, making it an excellent choice for irrigating gardens. On the other hand, it does not have fluoride, which is essential in maintaining good oral health and warding against tooth decay.

Are There Any Drawbacks To Collecting Rainwater To Use Later On?

final question

final question

Homeowners that rely on rainwater harvesting must contend with the potential for dry weather, storage limitations, and the need for routine maintenance. That is in addition to the initial investment required to set up a harvesting system.