Rainwater harvesting, alongside enhancing green living, is also supposed to be the best and most effective way to end water scarcity at household level.
“Water is our most precious resource, but we waste it, just as we waste other resources, including oil and gas” – David Suzuki
Water is essential for our day-to-day needs besides playing a pivotal role in bettering and making healthier the lives of people. The rapidly increasing population, urbanization and industrialization have led to a manifold multiplication in the demand for processed supply water. The only way forward in this scenario besides conserving this precious resource by using it judiciously; is tapping alternate sources of water. Understanding this, rainwater harvesting is fast emerging as the most acceptable and viable solution to help solve water crisis problems for various sectors across both rural and urban segments.
Rainwater harvesting has been practiced since times immemorial. Touted to be the most acceptable and sustainable solution to alleviate water crisis issues across the world; this system involves collection and storage of rainwater from the surfaces it falls with the objective of using this stored water at a later stage for domestic, commercial or agriculture purposes.
Gharpedia brings for you a look at – the multiple benefits of rainwater harvesting; rainwater harvesting models and their basic components; suggested amount of rainfall that can be collected; various ways of collecting rainwater along with their pros and cons; and uses of the collected water. In this blog, the discussion will be restricted to harvesting only and not “Rainwater Recharging”, which is generally employed to recharge open wells as well as bore wells or tube wells.
Benefits of Rainwater Harvesting
While the benefits of collecting and storing rainwater are aplenty in the industrial sector; one cannot undermine the advantages of rainwater harvesting in the domestic sector too. Here’s sharing a few of the benefits of this socially acceptable and environmentally-responsible initiative for households:
- Promotes water conservation by reducing groundwater and municipal water dependency.
- Saves money on water bills.
- Provides one with an excellent and valuable source of water in emergencies.
- Easy to install, operate and maintain for all types of houses and in all areas (rural, sub-urban and urban) with minimal investment.
- Reduces rainwater runoff and solves drainage problems.
- Provides an ideal solution in areas facing dire water shortage.
- Sizeably reduces the consumption of potable water.
- Provides a relatively clean and absolutely free source of water.
- Facilitates total control over one’s water supply.
- Promotes self-sufficiency.
- Offers a competitive water solution for landscape plants and gardens as it is non-chlorinated.
- Can be easily retrofitted to an existing structure or installed during construction of the house.
- Provides extremely flexible and modular systems; thereby facilitating expansion, reconfiguration, or relocation, if need be.
- Cuts down on energy cost of water movement as the collection source and usage points of harvested water are proximal.
Rainwater Harvesting Models
There are broadly two models associated with rainwater harvesting at the domestic level:
Rural Model of Rainwater Harvesting
In the hinterland where roofs of houses are generally built with sheets or Mangalore tiles, rainwater easily flows to the edges thereby facilitating its collection through gutters. Denizens then filter the rainwater through fine cloth. This collected water is used for – domestic purpose; agricultural needs; or for fulfilling the needs of the livestock.
Urban Model of Rainwater Harvesting
In urban locales the rainwater from the roof of the house is collected through rainwater gutters and stored in a storage tank; thereby supporting both potable (post water treatment) and non-potable needs of the family at their doorstep.
Basic Components of Rainwater Harvesting for House
- A catchment area which is generally the rooftop of the house.
- A conveyance system (perhaps piping) to help the captured rainwater travel from the roof to the storage area.
- A storage system (say a barrel, cistern or tank) to contain the rainwater for future use.
- A distribution system to transfer the water from storage to the usage area.
How Much Rain Can Be Collected?
The following formula can help you decide the amount of rainfall that you can collect:
1″ of rain x 1 sq. ft. = 0.623 gallons i.e. 2.8 liters or 1 cm of rain x 1 sq. ft. = 0.01m3
I.e. 10 liters.
This means that if you have a thousand sq. ft. (terrace) you can harvest 2800 litres of water within just 1″ of rain, i.e. if annual rainfall is 30″, you can harvest 84000 litres of water, provided you have the storage capacity. Normal tankers are of 5000 litre capacity, so you can harvest almost 16 to 17 tankers of water. Please note that our, total daily demand of water is 70 to 135 litre/day per person depending upon one’s lifestyle. Thus, a family of 5 can store around 125 days’ water requirement.
You may be confused about which type of tank can be used for collecting rainwater then, this article will help you to choose right one as per your needs.
Different Ways of Collecting Rainwater
All the methods mentioned below imbibe the same principles but differ in the scale of the system; the aesthetics; and water conservation effectiveness:
Rain Barrels Method of Rainwater Harvesting
One of the most simple, popular and people-friendly methods, this comprises of – installing a barrel at a gutter downspout to collect the rainwater. Basis the carbon footprint one wishes to save, this barrel could be either recycled or commercial.
- Can be easily adopted by anyone at any type of residence.
- Access to barrels is easy as they are readily available either at offline stores or on e-retail platforms.
- Barrels occupy extremely limited area so they are the best solution for small spaces.
- Limited storage capacity – around 50 to 100 gallons i.e. 225 to 450 liters.
- If unmonitored it escalates risk of water going waste as the barrel may overflow thereby defeating the very purpose of rainwater harvesting!
Dry System of Rainwater Harvesting
A slight variation of the rain barrel set-up, this entails a larger storage volume. To put it in a nutshell the collection pipe “dries” after each spell of rain since it empties directly into the top of the tank.
- Capacity to store a large amount of rainwater.
- Extremely apt for climates where rainfall occurs with infrequent, larger storm events.
- Quite economic to install.
- Ease of maintenance owing to simple system.
- Mandatory for the storage tank to be placed next to your house.
If you are using plastic tank as a storage tank, you must read this blog on plastic water tank for your safer side.
Wet System of Rainwater Harvesting
This system entails placement of collection pipes underground for connecting multiple downspouts from different gutters. The mechanism is quite innovative – as the rainwater fills the underground piping, the water-levels in the vertical pipes rise leading to spilling of the water into the tank. Certain mandates for the Wet System comprise – Watertight connections for the downspouts and the underground collection piping; and ensuring that the elevation of the tank inlet is below the lowest gutter on the house.
- Capacity to gather and conserve rains from the entire collection surface.
- Ability to collect from multiple gutters and downspouts.
- Tank can be set-up away from your house.
- Steeper costs due to underground piping.
- Mandate for availability of sufficient difference between the gutters and tank inlet.
We have also written article for benefits of gutter cleaning, have a look into it.
Precautions for Rainwater Harvesting
01. If one intends to use rainwater as a potable source then a filter mechanism is a mandate.
02. Allow the water collected from the first rains of the season to drain as it might contain pollutants from terrace, roof, etc. For this one needs to have a small valve installed at the bottom of the down tank pipe, so that the water from the first rains can be drained out.
03. Those living in highly polluted areas (due to emission of gases and suspended particles by industries) must refrain from rainwater harvesting.
Uses of Collected Rainwater
From the broader perspective we can deploy rainwater anywhere we use tap water. In fact, expending drinking water to flush our toilets and water our lawns reeks of wastefulness and irresponsibility keeping in view the growing population vis-à-vis the gross shortage of water across the country and even the world. Collection of rainwater not only lends a green hue to our home but also reduces our environmental footprint.
Basically rainwater can be tapped for – Irrigation Use; Non-potable Use; and Potable UseSome specific uses of rainwater include,
- Watering the lawn and plants in our garden by connecting the rainwater collection system to the irrigation/sprinkler system.
- Washing our vehicles and pets.
- Refilling our fountains, fish ponds and swimming pool.
- Washing our driveways and sidewalks.
- For all indoor non-potable fixtures say for example – toilets; washing machine; dishwasher etc.
- Post adopting adequate filtering and disinfection methods using it for all potable needs
- For industrial processes in lieu of municipally treated water
So what are you waiting for? This Environment Day resolve to do your bit for Mother Nature by taking a small but meaningful step towards selecting the most convenient rainwater harvesting practice from the ones Gharpedia has shared with you…
For those green warriors who wish to reduce the demand on mains water supply, hope exists in the form of rooftop and surface runoff rainwater harvesting methods. Opting for a compatible rainwater harvesting system is critical for making your home more sustainable.
Rainwater is one of the purest sources of water available at everyone’s doorstep at zero-cost.
Rainwater is a free and universally available commodity. Harvesting rainwater also becomes free post recouping the capital cost of the infrastructure collection system.
Huta Raval – An English Literature and Journalism Topper, Huta Raval has graduated from the L D Arts College, Ahmedabad. Post serving for 23 years in the NBFC and Public Library Sectors her desire for ‘writing the unwritten’ brought her to the creative field of content writing. Her clientele comprises of NGOs, Blogging Platforms, Newspapers, Academic Institutions, et al.