The global conversation around water scarcity has created a push towards water conservation. One of the most popularly cited techniques that encourages water conservation is rainwater harvesting for its low-cost and high efficiency. This technique requires minimal infrastructure changes, but an average roof can collect up to 600 gallons of rainwater for every inch of rainfall. However, is it okay to assume that rainwater is safe to drink? Let’s explore the pros & cons of this age-old technique to answer this question.
What is Rainwater Harvesting?
As the name suggests, this is the storage or collection of rainwater rather than allowing it to run-off and go to waste. Also known as rainwater catchment and rainwater collection system, rainwater harvesting systems range from simple rain barrels to more elaborate structures with pumps, tanks, and purification systems. A typical rainwater harvesting system contains the following key components:
catchment from where water is captured and stored or recharged,
conveyance system that carries the water harvested from the catchment to the storage/recharge zone,
first flush that is used to flush out the first spell of rain,
filter used to remove pollutants,
storage tanks and/or various recharge structures.
Source: Centre for Science & Environment
Here’s a detailed video on how to set up a rainwater harvesting system on your roof:
Benefits of Rainwater Harvesting
As climate change continues to exasperate uncertainty around the availability of freshwater fit for drinking as well as other domestic uses, rainwater harvesting definitely sounds like an ideal choice to ward off water insecurity. It’s simple, low-cost, good for the environment and ensures easy availability of water. Here’s a quick list of the easy-to-spot benefits of rainwater harvesting:
1. Independent Water Supply:
Did you know 1.8 billion people are projected to live in water scarcity by the year 2025, claims UN Water. This means water access is likely to become more expensive and difficult to come by. However, the rainfall that falls on your property & you can harvest on your roof is essentially free. All it takes is a method to harvest it into a tank or cistern for later use. So, with just a little bit of time and money invested in your own rainwater harvesting system can make you self-sufficient in the long-run.
Think about it, do you really need water from the municipality to water your garden? Rainwater surely is a better candidate for this as it helps conserve freshwater for drinking, cooking and other more appropriate uses.
2. It’s Good for the Environment!
By creating a suitable alternative, rainwater harvesting reduces demand for groundwater. In other words, it diminishes the need for drilling into aquifers and depleting the already scarce groundwater. Rainwater harvesting enables groundwater levels to be further sustained rather than depleted. In addition, rainwater harvesting can reduce stormwater runoff from a property. The elimination of runoff can reduce contamination of surface water with pesticides, sediment, metals, and fertilizers. (Source: Innovative Water Solutions)
3. It’s as Easy as it gets..
Installing rainwater harvesting technology is simple, easy to install and operate. Here’s a quick overview diagram showing how it works:
Disadvantages of Rainwater Harvesting
1. Unreliable Rainfall Patterns
The most obvious deterrent to the technique is unpredictable rainfall patterns as limited or no rainfall can limit the availability of water. This is primarily why rainwater harvesting can be an unreliable water source particularly in semi-arid conditions.
Rainwater harvesting is suitable in those areas that receive plenty of rainfall. If rain is unpredictable, the use of a rainwater harvesting system can be critical to capturing the rain when it does fall.
2. Requires Regular Upkeep
A rainfall harvesting system, if not installed and maintained properly can also become a breeding ground for water-borne illnesses and harmful bacteria. That also means that the system carries a one-time-high price tag.
Depending on the system’s size and technology level, a rainwater harvesting system may cost anywhere between $200 to $2000 and benefit from it cannot be derived until it is ready for use. Like solar panels, the cost can be recovered in 10-15 years, which again depends on the amount of rainfall and sophistication of the system.
3. Not Fit for Drinking!!
While rainwater can serve as a good alternative for domestic uses such as landscaping, washing etc, the truth is that it is not fit for human consumption. The CDC website suggests: While useful for many things, rainwater is not as pure as you might think, so you cannot assume it is safe to drink.
Rain can wash different types of contaminants into the water you collect (for example, bird poop on your roof could end up in your water barrel or tank). Rainwater can carry bacteria, parasites, viruses, and chemicals that could make you sick, and it has been linked to disease outbreaks.
Help others access clean water
Access to clean water is a fundamental human right that cannot be substituted. Project Maji is a safe water charity that is on a mission to provide clean water through various solar-powered water systems to various communities in Kenya and Ghana.
Families that benefit from these systems have reported back on improved health, sleep and overall health. If you’d like to participate in helping us bring more clean water to these families, please consider donating water here.