Use gray water: This is how families save over 320 euros every year!

Use gray water: This is how families save over 320 euros every year!

Drinking water is a valuable resource, especially in dry summer months. In Germany, households spend an average of over 30 liters of drinking water every day just to flush toilets. This immense amount raises questions about economical consumption, especially when it comes to the use of gray water. Gray water is domestic wastewater that is free of feces and coarse dirt, such as from showering, bathing and washing hands. It is important to differentiate: kitchen wastewater and toilet water are not considered gray water; the latter is referred to as black water.

By using gray water for applications such as toilet flushing, cleaning, laundry and garden watering, annual savings of up to 17,500 liters of drinking water per person and around 80 euros in water and wastewater costs could be achieved. For a typical four-person household, this adds up to around 320 euros annually. In Germany, each household uses an average of up to 80,000 liters for garden irrigation.

Advantages and challenges of gray water use

Using gray water offers the opportunity to reduce water consumption by almost 50%. According to the analysis of South German newspaper Personal care and laundry account for around 48% of drinking water consumption, underlining the relevance of gray water. Despite the high savings potential, the economic viability of gray water systems is often seen as problematic because the investments only pay off after years. Such systems are often particularly useful in apartment buildings, hotels or campsites.

The costs for installing a gray water system in a single-family home start at at least 5,000 euros. The integration of these systems is easier in new buildings. Cost-intensive retrofitting is usually required in existing buildings. Treated gray water can reduce drinking water costs and wastewater fees, but even after treatment it does not remain drinking water in the true sense.

Technical requirements and installation

Installing a gray water system requires separate piping systems and sufficient space for tanks, which usually vary between 250 and 15,000 liters. The system itself typically consists of water tanks, filter devices, pumps and a separate pipe system. The processing is carried out mechanically and biologically, with no chemical agents being used. Plumbing.org emphasizes that after treatment the gray water is germ-free, but does not reach drinking water quality.

If you want to take advantage of the benefits of gray water, you must also register your gray water system with the health department. The legal requirements that must be observed during installation can be better implemented by specialist companies as they are subject to the requirements of DIN 1988.

In summary, the use of gray water is a promising but complex approach to saving drinking water in the home. If used and planned correctly, households can not only save costs, but also make a significant contribution to a more sustainable use of water.