One conclusion of the Federal Environmental Agency: Because of high costs and hygienic problems is the use of rain water is not recommended that the drainage is better targeted.
comes in terms of the economics of the Federal Environmental Agency (UBA) concluded that a non-subsidized system is generally not currently charged. The construction costs for storage, pipelines, filters and pumps are loud authority in the range of 2.500 to 5.0000 € - depending proportion of own performance and the size of the memory.
A four-person household, which replaced a year on average 40 cubic meters of drinking water through rain water harvesting saves, at a price of two euros per cubic meter of about 80 € a year. When including the use of rain water even for washing clothes, a savings of 60 cubic meters, resulting in an annual financial savings of 120 €. The maintenance by a company must be also estimated at 100 € per year. In contrast, we get a year for investment of the construction costs at a rate of 2.5 per cent interest at 75-150 Euro.
contrast, is targeted infiltration of rain water, according to UBA good for the environment. Rain water is used, our aquifers regularly replenish. In many heavily populated areas of the natural water cycle is at risk. to get in or restore requires the use of rain water to break new ground.
rain water to use for garden irrigation is recommended without reservation. However, schont die Regenwassernutzung im Haushalt – etwa zum Wäschewaschen – wegen des geringen Spareffektes kaum das Grundwasser. Aus ökologischen Gründen ist die Regenwasserversickerung auch hier die bessere Alternative. Zudem führt, wie bereits aufgezeigt, Regenwassernutzung im Haushalt nicht zu einer echten Kostenersparnis, da Anschaffungs- und Wartungskosten bei korrekter Handhabung der notwendigen Installation vergleichsweise hoch sind und die Hygiene oftmals nicht ausreichend gewährleistet ist.
Peter Wohlfarth
Sachverständiger für Schäden an Gebäuden
