A rain water system basically consists of the following components:

Rain water collection pipe

The rain water collected in the roof gutters flows down the downpipe and is fed through the rain water collection pipe into the rain water storage tank.

Coarse and fine filters

Dirt, dust, organic residues and airborne pollutants accumulate on all roofs and these are washed into the guttering with the rain water. Before the rain water flows into the rain water storage tank, it must first be pre-cleaned using a coarse filter. The coarse filter can take the form of a downpipe filter installed in the downpipe, or the coarse filter is installed underground before the water reaches the cistern.

Thorough filtration before storage is always preferable. It is only necessary to use a fine filter upstream of the pump in existing water storage systems. If a suitable filter is installed before water reaches the storage tank no further filter should be used due the risk of microbial contamination. .


Rain water storage tank (cistern)

Der The rain water storage tank is used to collect rain water. The following points should be considered:

- The size of the rain water storage tank should be chosen depending on the roof surface area, the average precipitation volume, the intended use of the rain water and the number of people (rule of thumb: 1 m3 per 25-30m2 of roof surface area or per person, i.e. approx. 4-5 m3 for a 4-person household). Please use the form on page 13 in order to calculate the optimum size of a rain water storage tank tailored to meet your needs.
- Above-ground storage tanks and pipes must be impervious to light (to avoid the formation of algae)
- A temperature of 18 °C should not be exceeded (lowered in oxygen content)
- Underground rain water storage tanks offer many benefits since they can be buried in the garden or yard.
-Joints in reinforced concrete tanks should be mortared to make them watertight.
- Plastic tanks made from PE, PP and sometimes recycling granulate are well suited both as underground tanks or basement tanks
- The rain water storage tank may overflow in the event of heavy and prolonged rainfall and when little rain water is used. It is therefore necessary for a rain water storage tank to have an overflow pipe through which overflow water can drain away over the property or flow into the sewer network.

- When connecting the overflow pipe to the sewer network it should be equipped with an overflow siphon trap with rodent protection and backflow protection.
- A smoothing inlet is required in order to avoid agitation of the sediment layer (fine dirt and dust particles) at the bottom of the tank.
- Existing, unused septic tanks, wells, heating oil and gas tanks may be used as cisterns after appropriate inspection, cleaning and lining have been carried out.


Water extraction pipe

The following points should be considered:

-The water extraction pipe should be designed to be floating at the point where water is drawn off (adjusts itself to the current water level) and should have a suction filter (no fine filter).
- A food-safe, antimicrobial, spiral rubber hose has proven to be well-suited for use as the suction pipe in the rain water storage tank.
- The suction pipe from the rain water storage tank to the pump should be as short as possible and should run horizontal or rise slightly to the pump


Rain water Manager

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 drinking water operation as soon as there is too little rain water in the storage tank. In this case, drinking water is back fed within the building depending on requirements, guaranteeing a constant supply of water at all times.



Supply to the points of consumption

The RainwaterManager transports the rain water through pipes to the various supply points (WC, washing machine, garden tap etc.)


The following points should be considered:

- Stainless steel or plastic pipes should be used since rain water contains few minerals and often promotes corrosion.
-The pipes must be coloured differently from the drinking water pipes and must be labelled.
- Taps should be labelled „Do not drink“ and equipped with a child safety device.
- It is not permitted to connect rain water pipes with drinking water pipes