Expert shares rainwater harvesting tips to combat Dutch summer droughts

With increasingly frequent dry summers threatening gardens and green spaces across the Netherlands, residents are turning to smart and sustainable methods to capture and use rainwater. Beyond the traditional rain barrel, horticulturist Floor Korte told RTL about a range of practical options that help gardeners and homeowners make the most of heavy rainfall during wetter seasons to prepare for drier months.

The rain barrel remains a popular, simple system. Positioned under a roof’s downspout, it collects rainwater runoff in a container holding about 200 to 220 liters. However, its limited capacity means water runs out quickly during extended dry periods. Korte suggests connecting multiple barrels with a passage between them. “By placing a second barrel next to the first and linking them, you prevent overflow and increase water storage,” she told RTL. Additionally, she advises installing a filter below the gutter to keep leaves and debris out and prevent pipe clogs.

Winter freezing poses another possible challenge. Korte offers a straightforward solution: “Fill a plastic bottle halfway with water and let it float inside the barrel. The bottle moves with the water, helping to prevent ice formation and saving hassle.”

For those looking for larger capacity, underground rainwater tanks provide a concealed solution that can store significant volumes for garden and household use. Although installation can be more complex and costly, alternatives exist. Water bags, capable of holding about 1,000 liters, fit easily under verandas or crawl spaces.

Natural landscaping solutions also play a role. The wadi — Water Afvoer Drainage en Infiltratie (Water Drainage, Runoff, and Infiltration) — is a lowered green strip designed to collect rainwater and allow it to slowly soak into the soil. Floor Korte explained the environmental benefits: “Besides being functional and attractive, wadi areas support biodiversity. Occasionally, they turn into natural ponds where frogs or small fish can live, enriching the local ecosystem.” However, this method requires enough space and careful design to be effective.

For residents of new housing developments, infiltration crates or pits offer another underground system for rainwater management. These structures allow water to seep into the ground, replenishing groundwater and reducing stress on sewage systems during heavy rainfall. Korte notes this approach is mainly suitable for new builds and less practical for existing homes due to necessary modifications. Unlike other systems, infiltration crates do not provide stored water for irrigation.

A creative, budget-friendly alternative to traditional rain barrels is repurposing livestock watering troughs. Typically used for animals in pastures, these troughs hold about 1,000 liters and are often available secondhand for around 50 euros. Korte told RTL, “They make an affordable option with larger capacity for rainwater harvesting.”

For those interested in using rainwater inside the home, advanced systems with pumps, filters, and plumbing can supply water for toilets, washing machines, or cleaning. Though more expensive to install, these systems save tap water. A mid-range option is a hydrofoorpomp, which maintains constant water pressure and allows rainwater use for household appliances without the higher cost.

Finally, even city dwellers without gardens can participate. “A rain barrel on a balcony works well,” Korte told RTL. “Attach it to a downspout to collect rainwater for indoor use or for balcony plants. You share some of the water with neighbors, but once the barrel fills, excess water simply flows on.”