First Dutch housing estate to do laundry, flush toilets with rain water
For the first time in the Netherlands, a new housing estate is being built with a rainwater tank under each house. The buyers of the homes in De Buurt in Venhuizen (Noord-Holland) will do their laundry, flush their toilets, and sometimes also shower with rainwater from the tank instead of drinking water, RTL Nieuws reports.
Hemelwatertechniek is responsible for the rainwater tanks under the eleven houses in the estate. The tanks are filled by rainwater that falls on the roof of a house and flows via the gutter to the tank. “The size of the roof determines the size of the rainwater tank, because a larger roof means that the household gets more rainwater,” Hemelwatertechniek owner Antoon Vreeker told the broadcaster.
The houses in the estate vary in size. Some have a 6,000-liter tank under them, the larger houses have a 15,000-liter one. “A family of four can flush the toilet, do the laundry wash the car, and water the garden plants for an average of ten weeks with the small tank,” Vreeker said. The large tank has enough water to also use for showers. The grid water supply is also connected to the tank, so households won’t run out of water in times of little rain.
The rainwater is purified at the house. In homes where the water is used for showers, it happens in four steps. In the other homes, two. A drift filter ensures that all visible dirt like leaves or sand is removed. When the water enters the home, it passes through a carbon and micro filter, so that the water has a transparent color and doesn’t smell. A membrane filter removes even finer dirt particles. And a UV lamp kills the bacteria in the water.
Milieu Centraal is positive about the initiative. The Netherlands currently has enough drinking water, but due to the growing population and climate change, it is becoming increasingly challenging for drinking water companies to meet the demand. “It is good to realize that drinking water is not inexhaustible. Saving is important and this is one of the possible ways. And it makes sense if you consider that we now flush the toilet with great drinking water.”
The tanks also ensure that more rainwater is stored and less ends up on the street. “Especially during extreme rainfall, something we see more often, pressure can build up on the sewer. Because this initiative helps with that, it is something we applaud,” the Milieu Centraal spokesperson said.
Mirjam Blokker, who works for the KWR Water Research Institute and is an expert in the field of drinking water demand, has some reservations. She points out that, no matter how efficient, purifying the water per house will take more energy than central purification in one place. “And you mustn’t forget the cost of the tanks. The residents of the new houses pay for them, while the price of drinking water in the Netherlands is very low. You save on that by using rainwater. But if you want to earn back the cost of the water tank with the savings, it will take a very long time.”
