18 May 2024

Common mistakes to avoid in rainwater harvesting

Rainwater harvesting, an economical and environmentally-friendly solution, allows us to effectively utilise the most abundant natural resource - rain.

However, the successful implementation of a rainwater harvesting system requires meticulous planning and execution to avoid common mistakes.

Factors such as climate and terrain, proper installation of piping and drainage, secure sealing of storage tanks, routine checks of pH levels, pre-filtering of collected water, and appropriate management of storage tank levels are all crucial elements to consider for maintaining an efficient system.

Rainwater harvesting is not only a cost-effective alternative to traditional water sources; it also serves as a vital tool in conserving water and reducing dependency on traditional water supply systems. This eco-friendly solution capitalises on rainfall, an extensively available and renewable natural resource, transforming it into a viable water supply that can be used for myriad purposes such as irrigation, washing, and even drinking, following appropriate treatment.

However, the process of rainwater harvesting isn't as simple as simply collecting rainwater in a storage tank. It demands careful planning, precise execution, and regular maintenance to avoid common pitfalls and ensure the system functions efficiently.

Managed correctly, this invaluable resource can provide a sustainable, self-sufficient water supply, providing a significant contribution to water conservation efforts and promoting self-sustainability.

In this post, we dig into some of the common mistakes to avoid when contemplating whether to install your own rainwater harvesting system and talk you through the ways to avoid these potential pitfalls.

6 common mistakes to avoid when installing a rainwater harvesting system

There is a rise in the number of homes and businesses looking to install rainwater harvesting systems around the world and whilst this brings with it many benefits, there are some common mistakes to avoid if you are researching whether to install your own rainwater harvesting system. Here are six of the most common mistakes to avoid:

1.     Choose the right system for your climate and terrain

Choosing the appropriate rainwater harvesting system for your specific climate and terrain is paramount to its success. Some systems are better suited to arid environments where rainfall is scarce but valuable, while others are specifically designed for regions with heavy, frequent rain.

For instance, a direct pumped system may be better for areas with consistent rainfall throughout the year, as it pumps water directly from the storage tank to the point of use. Conversely, an indirect gravity system might be more suitable for hilly areas, where gravity can be used to direct the water from the collection point to its destination.

It's important to conduct a thorough assessment of your local climate, rainfall patterns, terrain, and your water needs before choosing a system. Making the wrong choice here could result in a system that does not meet your needs, or worse, one that doesn't work efficiently or effectively.

Picking the right system for your unique scenario can significantly increase the benefits you get from your rainwater harvesting efforts. This careful consideration helps ensure that you are not just harvesting rainwater, but doing so in the most effective, efficient, and sustainable way possible.

2.     Make sure your rainwater harvesting system is installed correctly, including proper piping and drainage

Proper installation of your rainwater harvesting system is crucial for its overall function and efficiency. This process involves more than just setting up a tank and expecting it to collect rainwater. A significant part lies in the correct installation of piping and drainage systems.

Ensure that the gutters and downpipes are correctly connected to the storage tanks, facilitating an unimpeded flow of water. It's also vital to establish an efficient overflow and drainage system to cope with excess water during heavy rain. Without this, you risk damage to the tank or even flooding your property.

Moreover, filters should be installed at appropriate points to prevent debris from entering and contaminating your storage tank. Regular cleaning and maintenance of these filters are also essential to maintain the quality of harvested water.

Finally, it's highly recommended to seek professional help for the installation to avoid common pitfalls. A poorly installed system is not just ineffective but could potentially cause more harm than good, leading to water wastage or structural damage. Therefore, investing in professional installation ensures your rainwater harvesting system performs optimally and stands the test of time.

3.     Ensure the storage tanks are securely sealed to avoid water loss through evaporation or seepage

Securing and sealing your storage tanks effectively is vital in rainwater harvesting systems, as it prevents unwanted water loss through evaporation or seepage. An unsealed or poorly sealed tank is susceptible to significant water loss, especially in areas with high temperatures or strong winds, which accelerate evaporation rates.

To mitigate this, tanks should be fitted with airtight lids or covers that not only prevent water evaporation but also keep out dust, insects, and other potential contaminants. The base and walls of the tank should be robust and impervious to prevent water seepage into the surrounding soil. Regular inspections for cracks or damage can help identify potential leaks early and ensure prompt repairs.

In addition, tanks should ideally be placed in shaded or cooler areas to further minimise evaporation. If this isn't possible, consider using insulating materials or tank coatings that can reflect sunlight and reduce heat absorption.

Remember, every drop of water conserved contributes to a more resilient, water-secure future. Thus, taking these steps to seal your rainwater harvesting system can make a significant difference in your water conservation efforts.

4.     Regularly check the pH levels of the harvested rainwater to ensure it is safe for consumption and irrigation

It's crucial to monitor the pH levels of the harvested rainwater continuously, as it's a significant indicator of the water's safety for use, whether for consumption, irrigation, or other household purposes. The pH level of water refers to its acidity or alkalinity, measured on a scale of 0 to 14. A pH of 7 is considered neutral, values less than 7 are acidic, and those above 7 are alkaline.

Rainwater usually has a slightly acidic pH due to naturally occurring substances it dissolves in the air. However, increased industrialisation and pollution can lead to the rainwater absorbing harmful substances, thereby affecting its pH level. A pH level that is too high or too low might indicate the presence of contaminants in the water which could be harmful if consumed or used for irrigation.

To check the pH levels, you can use a simple pH testing kit or digital pH meter, available in most home improvement or garden stores. The process is simple and can be done within minutes. If the pH levels are not within the safe range (generally between 6 and 8 for most uses), the water will need to be treated. Treatment options include neutralising filters or chemical additives. Regular testing and adjusting the pH as necessary will ensure that your harvested rainwater is safe for your intended use.

5.     Pre-filter collected water before storing it in tanks, as to remove debris, leaves, and other contaminants

Before storing the rainwater in tanks, it is essential to pre-filter it to remove any solid contaminants like leaves, debris, and dust particles. This step is especially crucial if the harvested rainwater will be used for consumption or irrigation. The pre-filtration process can be as simple as using a fine mesh screen at the collection point to trap larger particles. However, for greater purity, a more sophisticated filter system can be utilised, which can remove smaller particles and even some dissolved substances.

Various types of rainwater pre-filters are available on the market to suit different needs. For instance, a roof washer diverts and discards the first flow of rainwater, which usually carries the highest concentration of contaminants. On the other hand, a downpipe filter can be installed on the downpipe and works by separating the particles from the rainwater using a vortex principle.

Remember to clean and maintain your pre-filters regularly to prevent clogging and ensure that they function correctly. By incorporating a pre-filtering system in your rainwater harvesting setup, you can effectively enhance the quality of your collected water and ensure its suitability for intended uses.

6.     Don’t overfill or underfill your storage tank - always have a little bit of extra room to account for heavy rainfall or extended dry spells

When managing your storage tank, it is crucial to strike a balance - neither overfilling nor underfilling the tank. Overfilling can cause issues such as overflow and potential damage to your tank while underfilling might leave you short of water during extended dry spells.

To avoid overfilling, most tanks come with an overflow system that will divert the excess water once the tank reaches its capacity. However, it is still best to monitor your tank, especially during heavy rainfall, to ensure that the overflow system is functioning correctly.

On the other hand, underfilling your tank can be just as problematic. During extended dry periods, if you have not adequately filled your tank, you may run out of water. To prevent this, try to fill your tank as much as possible during wet seasons.

Finally, it's always a good idea to have a bit of extra room in your tank to accommodate any unexpected changes in the weather. This flexibility allows you to store more water during periods of heavy rainfall and provide a buffer during drier spells. Regularly monitoring your tank levels and adjusting your water usage accordingly will help ensure you maximise the benefits of your rainwater harvesting system.

One of the easiest ways to monitor the water levels in your tank is to use a water tank level monitoring system. At Smart Water, our innovative, market-leading water tank level monitoring system provides a wireless water tank management solution with mobile app connectivity, allowing you to manage and monitor the water you harvest from anywhere.

It is solutions like this that are helping people to manage their water more efficiently, understand their daily usage and allowing them to put in place measures to reduce usage whilst at the same time, collecting the rainwater from their property, adding to the overall sustainability and reducing the demand on water treatment and municipal water supply.


Ultimately, when it comes to installing a rainwater harvesting system, there are some common mistakes you should avoid.

Whether you make use of DIY installation tips or have the experts come to handle the task for you, ensuring successful rainwater collection starts with audience research, strategic accounting and setup planning.

At Smart Water, we are helping more and more people around the world to successfully monitor and manage their rainwater harvesting solution, contributing to increased sustainability.