Common Rainwater Harvesting Questions Answered
You are probably starting to be interested in rainwater harvesting (RWH) and whether it can become a feasible practice in your household. But like with all important endeavours, you must first orient yourself with the essential facts of RWH before you carry it out in your home or community. It pays to be aware of what it’s all about as well as what to do and what not to do so you can set up the system with ease.
Here are some common questions about RWH answered:
- What is rainwater harvesting (RWH)?
RWH is the practice of collecting, storing, and using rainwater for various purposes in the household or community. The rainwater can either be stored and used directly or redirected to recharge groundwater or a borewell. Simply put, it is the technique of gathering rainwater and storing it for later use.
- Who can take advantage of RWH?
Practically everybody, provided they have the means. But RWH is a low-cost venture so even families with strict budgets can practice it.
- Why should I practice RWH?
There are the personal advantages it can provide your household. You can cut down on the amount of water you consume from your regular municipal supply and thereby lower your bills. Also, in case of a water shortage, you are sure to have a backup supply.
There are also the advantages to your community. Rainwater is the primary source of fresh water in most areas in the world. At times when rainfall is erratic—that is, it falls in short bursts but at high intensity—the rain that falls on the earth’s surface flows away fast, which gives the groundwater less chance to recharge. This is often the reason why water scarcity happens. With RWH, the rainwater you store can be used directly for your needs, or you can use it to recharge groundwater and do your community a good turn.
- Where can it be practiced?
RWH can be practiced beyond the home. People in schools, businesses, institutions, and any other similar establishments can practice RWH as long as there is an open space in which they can capture rain, or what is usually called a “catchment area.” Farms can also take advantage of RWH for their irrigation and agricultural needs.
- Can the rainwater be used for drinking and cooking?
Yes, Rainwater is the purest kind of water there is. However, it can become contaminated when it comes in contact with pollutants in the air or on surfaces. For this reason, if you live in the city air pollution makes drinking rainwater inadvisable. There are filters you can use to remove such heavy metals and other toxins, most councils and local government authorities advise against drinking rainwater collected in urban areas.
If you live in a more rural area, then you can drink your rainwater and use it to cook or shower. It is still advisable that you filter it with multi stage filtration before you use it for drinking and cooking purposes. The types of filters in a multi stage system depend on what you are trying to filter from the water and may include UV or reverse osmosis filters, as well as other types of filters like sediment and charcoal filters.
- How much rainwater can be collected?
It really depends on various factors, such as your area’s rainfall pattern, the catchment area, and the type of collection system used. For you to completely understand the potential of RWH, let’s do some calculations. Let’s say your house has a catchment area of 80 square meters. If the average annual rainfall in your area is 700 millimetres and we’re assuming a 70% harvesting efficiency (since some rainwater will be lost because of factors such as evaporation, etc.), you can calculate your harvested rainwater as such:
Volume of RW harvested = 80 × 0.7 × 0.7
= 39, 200 litres
This total volume is more than what a regular family of five persons would consume as drinking water in a year. You can imagine the possibility of savings you can get from that scenario. You can invest in a filtering machine to filter the rainwater you’ve stored, and then you’ll have instant drinking water any time you and your family need it. You’ll no longer have to spend a lot on buying mineral water bottles for your drinking needs.
Rainwater harvesting isn’t actually a new trend. It is a household practice that can be traced back to a thousand years, especially in countries where rainfall tends to be erratic. If you haven’t tried it yet, now is just as good a time as any, provided you use a reliable supplier for your rain water tanks and containers.