Using free rain water allows for up to 50 % of the potable water needs of a family household to be replaced in applications where potable water is not required. The savings in commercial and public systems can amount to over 90 %.
On average, an annual 400 to 2,000 liters of water per square meter rain down from the sky in Germany. For that reason, rainwater systems can be operated everywhere without restriction. Obviously the amount of rain differs across the nation. There is less rain in the North an East of Germany, making it sensible to use these lower amounts of water as optimally as possible. In the South, there is significantly more precipitation. However, the summer months are oftentimes extremely dry and longer periods of drought need to be dealt with.
A variety of applications such as toilet flushes, washing machines, garden watering and cleaning can use rain water owing to its particularly high quality. Especially watering the garden can require considerable amounts of water, creating a large saving potential. An average 60 liters are used for this purpose, amouting or even surpassing 50,000 liters annually for a medium-sized garden. And thanks to climate change even longer dry periods in summer are to be expected, increasing the water need. In industry and commerce, there are additional uses that enable significant savings in water consumption.
There are many advantages to using rainwater. Saving potable water lowers your water bill and contributes to saving the environment. However, there are additional benefits for household and garden due to the special properties of rainwater:
- in toilet flushes: less urine scale formation
- in washing machines: 50 % less washing detergent
- in watering gardens: promotion of plant growth
A modern rain water utilisation system consists of two basic components:
The RainwaterManager, a compact central management unit with a pump, control equipment and automatic potable water backfeed and the rain water storage tank with an integrated filter, smoothing inlet, floating extraction device and overflow pipe.
The RainwaterManager is installed inside the building and the rain water storage tank is located either in the ground outside or in the basement. The RainwaterManager controls the system and ensures operational reliability. This is where the water is drawn out of the storage tank and transported to the supply points in the building. At the same time, it monitors the water level in the cistern and automatically switches to potable water operation as soon as there is too little rain water in the storage tank. In this case, potable water is back fed within the building depending on requirements, guaranteeing a constant supply of water at all times.