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How To Choose A Rainwater Harvesting System

Choosing a suitable rainwater harvesting system can be a daunting task, especially when there are a vast array of systems in the market.

The technicalities and functionalities of each system could differ from one another, which makes comparing systems difficult.


Choosing the right system for your home or project doesn’t mean that you have to be burdened or too bothered by these technicalities. Rather, what could lead you to your “perfect rainwater harvesting system” are only 3 simple but important considerations/guiding principles.

1. Capacity & Usage

What will you be using the conserved rain for?

Will you be using it for toilet flushing, landscaping, car washing or general washing?

watering plant

Simple logic will tell you that if you are going to use rain only to water your moderate piece lush garden, there is no need to go for a giant-sized rain tank.

As simple as this may seem, we have received many requests for large rain tanks for small-scale usage.

So now that you are clear with your rain harvesting objective, how much water do you typically use for these activities?

Some of our more conscious customers have been able to tell us exactly how many litre goes in to their garden, for example. However, if you have never kept tabs, there is nothing to worry about.

During the information gathering stage, a rain harvesting specialist should be able assist in estimating how much water is used in your daily activities.

For plant watering, we do so based on your gardening land area size.

For toilet flushing, we do so by considering the number of people & number of toilets in the house, among other variables, for example.

Why is knowing your water consumption important?

That is to enable you to work backwards in determining how large a tank you require & how much water you will eventually save. 

With the help of meteorology data, we also consider the frequency of rainfall to estimate how often the tank gets filled.

Why is getting the “right size” important?

There are more drawbacks in bigger tanks than in smaller ones.

Not only bigger tanks would lead to wastage if you end up using much less, there is something about tropics with abundant rainfall like Malaysia which you need to understand.

If only a small portion of rain is used while the bulk of it stays stagnant, still rainwater would potentially cause problems like algae growth & mosquito breeding.

Users who have experienced these issues often end up emptying their rain tanks and calling rainwater harvesting a day – which is, again, wasteful.

This is the reason why we built Voda Rainwater Harvesting System in such slim dimension – to enable constant water movement.

People who go for bigger tanks are also often under the impression that bigger tanks means saving more. Bear in mind though, the amount you collect does not always equal to the amount saved.

The amount of water saving ultimately depends on you.

How much rain are you willing use (i.e. to what extent are you willing to let rain substitute water)?

Studies have shown that almost half of an average household’s water consumption goes into non-potable uses. This means that, if you are willing to use rain to its highest potential, you can be comforted that you’ll enjoy some 50% slash in water bill at the very least.

2. Type of System & Maintenance Involved

Rainwater harvesting systems are broadly categorised into conventional and unconventional systems.

Conventional systems are mostly stored on the ground or underground. The commonalities with these tanks are they are often bulky (suitable in countries with long durations of dry spells) and use electricity pumps.

Conventional Systems
Conventional System

On the other hand, unconventional systems are gravitational – which means rather than using electricity, they function on gravity. Because of this, most unconventional systems are parked at a high altitude, be it in roof attic or on a concrete slab high up.

Unconventional Systems
Unconventional System

Conventional tanks do have its plus. They store a substantial amount of water and are very suitable for large-scale developments. Nonetheless, the usage of pump may mean that it is not environmental friendly, it jacks up the cost of a system and it requires regular maintenance. Its bulkiness also requires a large storage space. This could be why there is a changing preference to unconventional systems, especially among landed developments and residential premises.

People who go for bigger tanks are also often under the impression that bigger tanks means saving more. Bear in mind though, the amount you collect does not always equal to the amount saved.

The creation of Voda was essentially premised on the goal of overcoming these issues. By wall mounting the system, we are able to achieve space efficiency, zero carbon capability, affordability and easy maintenance all at once.

rainwater harvesting in malaysia
Wall-Mounted Voda Rainwater Harvesting System

Aside from these 2 broad categories, there are also DIY systems. We have visited homes who built their own systems. Some were successful and have continued to use it. Others, whose tanks became breeding grounds for mosquitoes, ended up dismantling the tanks. Therefore, it is important to choose a tank with practicality in mind.

3. Price

We applaud people who harvest rain voluntarily out of protecting our dwindling water resource.

Despite the rising cost of living and the low water tariffs, they invest in rainwater harvesting any way even when they didn’t have to.

We believe these users understand the big picture of why rainwater harvesting has become an urgency.

Even then, this doesn’t mean cost efficiency is not an important consideration.

Prices of rainwater harvesting systems, ranges between RM2,000 and RM10,000, and may even go up to RM25,000 depending on how sophisticated you want your system to be.

In determining this, it is utmost imperative to have consideration #1 Capacity & Usage well defined. Otherwise, you may find yourself buying features you don’t need.

For example, we would never urge customers to purchase the First Flush Diverter/System if they only want to harvest rain for garden use.

For the benefit of those who don’t know, the First Flush Diverter/System helps trap the first 10%-15% of the rain which normally contains contaminants caused by birds’ droppings, aged roof or even acid rain; the feature is normally a second-tier cleaning mechanism as a rainwater harvesting system would already be equipped with a Filter by default.

Of course, customers can always opt for the First Flush Diverter at their own discretion but it is not necessary.

Likewise, if your premise has a sizeable slab where your rainwater tank can sit on and you are not too particular about water pressure, then it is not necessary to go for a pump-equipped rainwater harvesting system.

Overtime, we have learned the differing needs among users and have made other variations to meet them.

Although Voda has the ability to solve most issues in rain harvesting and can be used for a variety of usage (both toilet flushing & various irrigation), sometimes customers are on a lookout for a simple no-frills system just for minimal usage like gardening.

That was why we debuted Voda Cylinder, a no frills ground tank with a minimalist design. Apart from affordability, the beauty of Voda Cylinder is that it also comes with various sizes and price points that could meet any requirement.

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Rainwater Harvesting System set up by the Voda Team in Sek Men Jenis Kebangsaan Dindings, Sitiawan. We estimate the school to be enjoying at least 50% savings in

Making the right choices could save you a ton of money. Therefore, it is crucial to engage a rainwater harvesting specialist that could offer you various options to arrive at the most optimum one.

If you require more help on this topic, we’d be happy to assist. Contact or write to us here.