Rainwater tanks in Belgium: maximizing benefits and water quality

In a country as environmentally conscious as Belgium, installing a rainwater tank is a sustainable step towards reducing water bills. But, it’s not just about collecting rainwater; it’s about ensuring the water you collect is of the highest quality.

rain barrel

Finding the Perfect Size

Choosing the right size for your rainwater tank is crucial. A tank that’s too large might lead to water stagnation, increasing the risk of sediment buildup and unpleasant odors. On the other hand, a small tank might run out of water quickly, forcing you to rely on municipal water.

To determine the ideal tank size, consider the following factors:
– The number of people using the water.
– The intended uses for the rainwater (e.g., gardening, flushing toilets).
– The size of your roof, which determines potential collection volume.
– The season when you’ll use the tank the most.

Never Underestimate Water Filtration

While setting up a rainwater tank is relatively straightforward, ensuring the water remains clean is paramount. Ideally, place your tank near a downspout. Using a gutter collector, which fits directly within the downspout, can be beneficial. Some collectors come with filters that prevent debris, leaves, twigs, and insects from entering the tank. This results in clearer water and reduces sediment buildup. If your collector lacks a filter, consider installing mesh screens on your gutters. Additionally, an overflow mechanism can redirect excess water into the stormwater system, preventing tank overflow.

Indoor vs. Outdoor Tanks

There’s a myriad of rainwater tank models available, with some of the largest ones holding up to 10,000 liters. Most tanks are designed for outdoor, above-ground placement. However, you can also install tanks indoors, such as in garages, basements, or cellars. Some larger tanks can even be buried underground. Regardless of the tank’s location, ensure it’s placed on a flat, stable surface, away from overhanging vegetation to prevent debris from falling in.

Maintaining Your Rainwater Tank

A common oversight is neglecting the maintenance of rainwater tanks. To prolong the tank’s lifespan and ensure water quality:
– Empty the tank during winter to prevent freezing, which could damage the tank’s structure.
– Annually, if possible, dismantle and clean the tank components.
– Regular maintenance might seem trivial, but it’s essential for the tank’s longevity and water quality.


Belgium’s climate and environmental ethos make it an ideal place for rainwater harvesting. By choosing the right tank size, ensuring effective filtration, and committing to regular maintenance, homeowners can enjoy the dual benefits of cost savings and eco-friendliness. As the world moves towards more sustainable practices, embracing rainwater tanks is a step in the right direction for a greener future.