Toilet water - Use rainwater
It is completely unnecessary to use drinking water for toilet flushing. The required process water does not have to be of food quality.
Collecting process water for the garden and toilet
If water is only used to irrigate the garden, smaller vessels such as rain barrels are generally sufficient. These should be filled via a filling machine in the downpipe of the roof drainage. These vending machines filter the coarsest dirt out of the water.
Rainwater, which is used to flush the toilet, requires greater care. A flush consumes about six liters of water, with ten flushes a day, 60 liters of water per day are needed. So that even with prolonged drought water is always present, larger storage tanks are required. The water spoils, therefore, a properly built cistern is required ...
Domestic hot water - a cistern is needed
To flush toilets, greywater, ie the waste water of washing machines, showers or bathtubs are suitable. But also rainwater can be used. Greywater is more difficult to store because of the residues, so rainwater is the better solution.
Cisterns are all clean and light-tight containers. Most of the collection containers consist of concrete or plastic. Concrete cisterns are usually located underground near the house, while plastic containers are suitable for both the basement and the underground storage.
The water coming from the roof flows through a filter in a pipeline to the bottom of the collection container. In the upper area there is an overflow, through which water flows from a certain level into the sewage system. The removal takes place via a pump, which is floating on the surface. In this way, polluted water can settle on the floor, while the clean water on the surface flows into the domestic water pipes of the house.
Normally a domestic waterworks is required, so that the process water has a constant pressure. Since great care is required during installation, a specialist should accompany them.
Necessary Installations in the House
Every house needs a drinking water supply, rainwater can not replace them. In general, domestic water and drinking water must not mix, the statutory provisions of the standard DIN 1989-1 must be observed.
In the house, therefore, a second pipe system is needed, which supplies the cistern of the toilet with rainwater. Since new lines for the water supply of the toilets are necessary anyway, it makes sense to connect the washing machine to the system as well.
A faucet for service water, for the removal of cleaning water, is also recommended. For other uses, such as dishwashing, rainwater is unsuitable.
When to upgrade
It is usually not worth adding a rainwater system to an existing water supply. If new lines are required anyway during renovations or new construction, the costs for the additional line system are kept within reasonable limits. In such cases, builders should also think about a tap water supply through rainwater.
The local banks will inform about possible subsidies for the facilities. By the way: The supply of all toilets in the house with rainwater is usually expensive and complicated, with washing machines it often looks different: If all the washing machines of the house in the basement, it is usually worthwhile to draw a line to these. Washing with rainwater is gentle on the laundry and also saves detergent.