Advantages of flushing toilets with rainwater
- No limescale deposits: Rainwater is naturally limescale-free, which means that it leaves no limescale deposits in the sanitary facilities. This protects valves and seals and significantly reduces the amount of cleaning required.
- Conservation of groundwater: Using rainwater instead of tap water reduces groundwater consumption. This is particularly important in regions with limited water resources and helps to stabilise natural groundwater levels, which supports local ecosystems. In addition, the pressure on the municipal water supply is reduced, which reduces expensive infrastructure investments.
- Environmental protection: Using rainwater to flush toilets is environmentally friendly. Unlike tap water, which requires energy-intensive treatment and transport, rainwater requires no such treatment. Six to nine litres of valuable tap water are saved per flush, which reduces the environmental impact. In addition, the sewerage system is relieved as less rainwater enters the sewers.
- Cost savings: Using rainwater reduces running costs, as tap water is becoming increasingly expensive. At an average cost of just under €2 per cubic metre of tap water, rainwater offers a free alternative for flushing toilets and therefore significantly reduces the water bill.
Technical requirements and cleaning with the WISY 4-stage system
The requirements for a rainwater harvesting system are well known, clearly defined and standardised. An efficient filter and treatment system removes impurities from the rainwater to make it suitable for storage in the cistern. Typically, such a system consists of various stages that purify the water and regulate the flow into the cistern before it enters the domestic water system.
The WISY 4-stage system offers an optimal solution for rainwater treatment:
- WISY rainwater filter: removes coarse dirt and particles.
- Calmed inlet: Prevents sediment from being stirred up at the bottom of the cistern.
- Floating extraction: Extracts the water just below the surface, where it is cleanest.
- Overflow siphon: Diverts excess water and prevents the backflow of dirt and odours from the sewer.
A separate service water network prevents the mixing of mains water and rainwater. A separate pipe is installed for flushing toilets. The water storage tank, the cistern, stores the collected rainwater until it is needed.
The rainwater system is controlled by the WISY rainwater unit. It ensures an automatic switchover to mains water if the cistern is empty and provides a standard-compliant separation between the public water supply and the rainwater pipe .
Saving up to 50 % tap water in the household through rainwater utilisation
Rainwater can cover up to 50% of household water needs, including toilet flushing, garden irrigation, washing machine and cleaning. This versatile use demonstrates the potential of rainwater to conserve water supplies.
Legal provisions and fees for rainwater utilisation
No authorisation is required to use rainwater for flushing toilets. The wastewater charges are the same as for tap water, as the rainwater used also flows into the wastewater disposal system.
Maintenance and care of the rainwater utilisation system
A correctly installed rainwater system is low-maintenance. The WISY vortex fine filter only needs to be inspected once or twice a year and cleaned in the dishwasher if necessary. The WISY 4-stage system eliminates the need for regular cleaning of the cistern forever, making the use of rainwater very simple and low-maintenance.
Frequently asked questions (FAQs)
Conclusion on rainwater utilisation for toilet flushing
Rainwater utilisation for toilet flushing offers numerous advantages:
- No limescale deposits
- Less groundwater consumption
- environmental protection
- cost savings
A well-installed rainwater utilisation system ensures a reliable water supply and requires minimal maintenance. Overall, it is a sustainable and economical solution for every household and helps to conserve valuable public water resources.