The importance of harvesting and utilizing rainwater has increased manifold in the face of the global water crisis. The rain has been used as a source of water since the start of human civilization. It is vital for our crops, reduce pollution, and keep the scorching summer season in control. Rains are pleasant as well and not only add to the beauty but also uplift your mood.
Have you ever thought about harvesting (storing) rainwater for later use? Stored rainwater can help you get your water-related chores done; you can even use this water for drinking purposes after proper filtration.
Rainwater was considered to be one of the purest sources of water, but owing to increased air and water pollution, it is undrinkable. The gases and particles present in the air give rise to acid rain, which is harmful to your health. However, after treatment, rainwater can be used for various purposes and even for drinking. Once it has been treated properly, it is 100% fit for drinking.
In this article, we will guide you about storing rainwater, filtering, and making it usable for various purposes.
Let’s save some rainwater and play your part.
Definitive Guide to Rainwater Harvesting and Filtration
Harvesting rainwater is not a difficult thing to do, but you need to set up the system by using different equipment, tools, and stuff. All the tools can be found online and in hardware stores nearby. Before we look at the things you will need, let us look at the benefits you can get from rainwater harvesting.
Benefits of Rainwater Harvesting
- The water collected from rainwater harvesting is free. The only costs are setup and filtration costs.
- You play your part in environmental conservation by utilizing rainwater that would be wasted otherwise.
- Rainwater works as an alternative source of water when tap water or well water is not available or short on supply.
- Rainwater is low on sodium. It is excellent for people who want a low-sodium diet plan.
- Harvesting rainwater avoids flooding of water drains.
- Rainwater is best for irrigation purposes and watering your lawns.
- Rainwater saves you a reasonable amount of money on water bills.
- By harvesting rainwater, you play your role in saving water for your countrymen, and in turn, you provide them with water.
- Rainwater harvesting helps you and your kids learn to save the most crucial element in our earth. It will teach them to survive during hard times.
Setting up the Harvesting System
For a small home, setting up the rainwater harvesting system is not a difficult but time-consuming thing to do. It is one of the best DIY projects with excellent results. You will be proud of yourself once you are finished with it. After reading this guide, you will be able to set up a harvesting system for your home.
You will need the following things to set up the harvesting system.
- Catchment Surface
- Gutters and Downspouts
- Leaf Screens
- First-Flush Diverters
- Roof Washers
- Storage Tanks
- Pressure Tanks and Pumps
- Treatment and Disinfection Equipment
- Security Equipment
- Drill Machine
The last 4 things are not needed as the core items for setting up the system; you need them as additional tools to facilitate your work.
Let’s look at the basic purpose of each thing, how to set it up, and how it helps in constructing an effective rainwater harvesting system.
The Catchment Surface – As the name indicates, it is used to catch all the rainwater that falls on your rood. A catchment surface is a smooth plank-like structure; if your roof is smooth, you do not need to install a special catchment surface. You can enhance the capacity by installing additional open-sided barn called rain barns. It increases the catching capacity and also provides a shed to keep your bikes, generators, lawn mowers, and other appliances safe from rainwater.
The surface of the catchment may impact the quality of the water collected. Metal, concrete, clay and asphalt shingle are commonly used as catchment surface. Each has its pros and cons, but all of them are best and do not alter the quality of water. Catchment surfaces made from slate are the best, but slate is very costly, and it may increase the overall cost very much.
Gutters and Downspouts – Once the water is collected on the catchment surface, gutters and downspouts come into play. They are used to transfer water towards the collection-drums or containers. Gutters help capture the rainwater, which will be wasted from edges of the roof. It is best to look for gutters made without lead as lead is harmful to your health, and it can contaminate rainwater. Aluminum gutters are best and are usually used by people collecting rainwater at large scales. Make sure that the gutter is properly installed between roof valleys so that you reduce water wastage and collect maximum water. Downspouts transform the water towards the collection tank and water filtration plant.
Leaf Screens – Leaf screens help catch the tree litter and tree leaves that may gather on the roof and flow with the water towards the container. It is vital to install a leaf screen as the debris can be very harmful to the entire process. Please keep in mind that you need to clean the leaf screen during a rainy season as it can get clogged and cause congestion and interfere with the entire process. Some systems may require a leaf guard. It is necessary for locations with a tea overhanging. Leaf guards are usually ¼ inch mesh screens; they fit along the entire length of gutter and provide effective protection from leaves and tree debris. Cleaning leaf guards is more complicated than cleaning a leaf screen. Leaf screens come in different shapes such as funnel-type downspout filter, strainer baskets, and filter socks.
First-Flush Diverters – First-flush diverters are used to route the first flow of water from the catchment surface away from the storage tank. The roofs have dust, insects, tree debris, and animal feces. These things are harmful and cannot be filtered from filtration systems. First-flush diverters ensure that this water is routed towards a plantation area. These diverters are made from PVC. It is filled first during rain, and the rest of the water which does not contain any debris is diverted towards the storage tank. It works like a small storage tank to get filled first and then rout the comparatively clean water towards the storage tank. During rain, the diverter is cleaned through a small hole leaving behind the debris. The diverter can be cleaned by opening the PVC structure later on once the rain is over. There are various types of diverters available in the market. You need to consider the amount of rainfall, number of dry days, debris amount, and roof surface before buying a diverter.
Roof Washers – They are placed just behind the main storage tank and are ideal for filtering debris for potable and irrigation systems. They provide additional protection for your drinking water and can reduce the load on your main filtration system. Roof washers have a capacity of 30-50 gallons and come with an excellent filter of 30 microns. Make sure that you keep your roof washers clean. Without proper and regular maintenance, the filters will become clogged, and water will not pass from it. If some water manages to enter the main storage tank, it will contain a lot of dirt and debris.
Storage Tanks – The water then moves to the storage tank. It is the most expensive component of the entire system. There should be no compromise on quality while selecting the storage tank as it can lead to water contamination. Whichever material you are choosing for a storage tank, make sure that it has zero impact in the water being stored in it. You can select from fiberglass, polypropylene, wood, metal, concrete, or in-ground concrete tanks. Several variables like rainwater amount, catchment surface area, utilization and demand, the length of dry days (without rain), aesthetics, budget, and your personal choice come into play while selecting the storage tank. A good storage tank will have the following characteristics.
- Storage tanks must be opaque, as they inhibit the growth of algae, fungus, and bacteria.
- Potable storage tanks must not have any unapproved material used in them, and they must not have been used for handling any toxic liquids.
- The material should be able to withstand sunshine, thunderstorms, and extreme weather conditions.
- It must be properly covered to avoid the influx of mosquitos and insects.
- The storage tank should be easily accessible for cleaning purposes.
One more thing to keep in mind while installing the tank is to place them in proximity to the supply and utilization points. It helps in reducing the distance water is traveling. It also lowers plumbing costs significantly.
The table below explains the storage tank material, features, and cautions you need to have with each material.
|Trash cans (20-50 gallon)||commercially available; inexpensive||Use only new cans|
|Fiberglass||commercially available; inexpensive||must be sited on a smooth, solid, level footing|
|Polyethylene/polypropylene||commercially available; inexpensive||the UV-degradable and must be painted or tinted|
|Steel drums (55-gallon)||commercially available; inexpensive||verify prior to use for toxics; prone to corrosion of the rust;|
|Galvanized steel tanks||commercially available; inexpensive||possibly corrosion and rust; must be lined for potable use|
|Concrete and Masonry|
|Ferrocement||Durable & Immovable||potential to crack and fail|
|Stone, concrete block||Durable & Immovable||difficult to maintain|
|Monolithic/Poured-in-place||Durable & Immovable||potential to crack|
|Redwood, fir, cypress||attractive, durable, can be disassembled and moved||Expensive|
Pressure Tanks and Pumps – It is impossible to create a gravity-fed pressure system at a local rainwater harvesting system. The best way to create pressure is to use a pressure tank and pump. They are connected after the storage tank and help in generate water pressure for your use. Most of the pumps are electrically powered. You just need to turn it on before using the rainwater, and it will supply you with enough water pressure to meet all your needs.
Treatment and Disinfection Equipment – If you are planning to drink rainwater, you will have to be very vigilant. For basic protection, you will have to use a disinfectant and filtration plant right at the harvesting system to kill all the bacteria; you may need to add chlorine in the water for enhanced disinfection. Chlorine is used regularly by municipal water treatment plants to disinfect the water. You can use a 3-stage filtration system, a reverse osmosis filtration system along with UV light, and a re-mineralization stage. Applying the above filtration systems will give you the best drinking water. The quality, taste, and purity of this water will even be better than bottled drinking water and tap water.
Maintaining Water Quality
Once you have installed the system and have started to drink water from it. You need to make sure that you keep on getting pure water from it. Your little negligence can cause you some severe health issues. So it is better to consider the following points.
- Monitor the tank levels regularly during the rainy season
- Cleaning gutters, filters, and first-flush equipment and other equipment
- Cleaning tanks before and after the season
- Repairing leaks (if any)
- Changing water filters regularly on the recommended time
- Keeping all the disinfection equipment neat and clean and out of children’s reach
- Getting the water quality tested
How much water can be captured?
The amount of water you can capture depends on the volume of the rainfall. For every 1-inch rain, you can capture 0.62 gallons of water per square foot of the catchment area. These calculations are tough and will boggle your mind. You should focus on collecting the maximum amount of water, and that is possible if you install the system correctly and ensure that there are no leaks.
Can we rely on Rainwater Harvesting as the only Source of Water?
Some people will say that you rely on rainwater for your entire water needs around the year or specifically in the rainy months. Well, this may be true, but due to uncertainty in weather, you cannot rely on this method as the only resort. Yes, it is economical, and you can get pure water from it, but you may end up being short on water. If you want to use rainwater around the year, then you would have to calculate your total usage and install storage tanks equal to that amount. The best way to do this is to calculate the total amount of water gallons you have used during the last year, add some more gallons to it and then install the storage tanks. This method will take the one-time cost to a very high, and you will still be at the risk of having less rainfall next year. You will also be increasing your maintenance time and cost. You will also have to take more care of your roof and ensure that it stays clean during the rainy season.
Laws regarding Rainwater Harvesting
There is a misconception that rainwater harvesting is prohibited in our country. There are only 2 states, Colorado and Utah, which have imposed partial restrictions on rainwater harvesting. If you are a resident of these 2 states, you need to check the local laws before installing the system.