Even if rainwater collection is easier in the countryside than in the city, notably due to the available space for burying tanks, certain towns rally to reuse this essential resource.
This is why in 2005 the city of Saint-Denis (93) put in place a system to collect rainwater by renovating the market hall of its main market. There, rainwater is collected on the roof and stored underground in concrete cisterns. This water is used by the mechanical street-sweepers who pass by three times per week to clean the streets. According to Yannick Miquel, head of the city council’s environmental center, « the system is made up of 12 buried tanks with a capacity of 12,500 liters, with a filtration system ». Thanks to this ecological process, very widespread in Germany and relatively new in France, the city avoids using drinkable water. The city also puts in place a similar system for the watering of grassy areas of newly constructed schools.
In Yvelines, the city council of Mureaux refurbished the old town hall into a unit that was more functional, economical, and respectful of the environment. Alain Soucours, director of historic buildings and logistics, affirms that « roof rainwater provides toilet flushes with savings of 2000 € per year, compared to a classic construction. A 30m3 cistern collects water fallen from the sky to underneath the building ». In the case of drought, the “drinkable water” network automatically takes over.
Examples of this type are more and more common, such as in England, where large projects, following the example of Castle Vale in Birmingham, have been put in place. The automated system collects and filters (removal of leaves and debris) rainwater, and ensures its storage in the subterranean tanks, with a capacity of 45,000 liters. The water can be drawn for the needs of hygiene, washing machines, and watering gardens.