Domestic waterworks - what does that mean?
Domestic waterworks are devices that can be used for a wide range of applications and consists of a jet pump, a pressure vessel and a pressure controller. They transport water from the extraction point, for example a well or a cistern, to consumption points in the house or garden. In the house, operating toilet flushes or washing machines with well or rain water are the most common applications of domestic waterworks. In the garden, for example, they are used for watering plants, filling ponds or other cleaning work.
How do domestic waterworks operate?
Water is suctioned from the intake point and pumped into the pressure tank. This creates a buffer, which means that the domestic waterworks can always provide constant pressure by means of pressure control. The buffer tank also ensures that the domestic water system does not have to start every time a consumer is actuated. This protects the material and reduces power consumption. A distinction is made between domestic waterworks on the basis of their technical characteristics, such as the flow rate, the delivery head or the pressure tank volume. One example of domestic waterworks with excellent characteristics is the Einhell GE WW 9041 E. Irrespectively, pressure is also a particular technical feature, as the maximum shutdown pressure rather than the maximum delivery pressure is crucial here. This is the point at which the jet pump ceases to fill the pressure vessel according to the pressure control. Starting from this value, a pressure loss of 1 bar per 10 metres must be taken into account when choosing the appropriate domestic waterworks. This is particularly important for use in homes over more than one floor.
Why use domestic waterworks?
In addition to sustainability and the desire for self‐sufficiency, the purchase of domestic waterworks usually precedes the decision to use well or rainwater as an alternative to expensive municipal water and thus to save costs. And not without reason. According to Statista, flushing the toilet alone results in 27% of domestic water consumption. In addition, 12% is used for laundry and another 6% for garden irrigation and car care. This results in an average savings potential of 45% of the total drinking water consumption.
Using these figures as a guide, anyone can use their water bill to calculate how much money they can save by using well water or rainwater through domestic waterworks.
Are domestic waterworks the right choice for me?
If the savings potential for water consumption in your home and garden is so high that the investment in a well or a cistern with domestic waterworks and accessories would pay for itself within a few years, this definitely makes sense for you. However, whether domestic waterworks are the right choice for the operation of a well or a cistern, still depends on other factors. So it is a good idea to operate only wells with domestic waterworks. For a ramming well – the much cheaper well variant – the performance of domestic waterworks is usually too high and will result in a significantly reduced lifespan of the well. Furthermore, it should be noted that the maximum suction height for domestic waterworks is generally 7–8 metres. Beyond this depth, for physical reasons it is no longer possible to suction water. For areas with such a groundwater level depth, domestic waterworks are therefore not an option. In these areas a deep well pump would be required.
Regardless of the type of well pump, attention must also be paid to the immutable quality of the groundwater. In the case of water containing iron, this may result in unsightly deposits in the toilet despite using an iron filter. And operating a washing machine with rusty well water is unthinkable. There are also restrictions when using a cistern. When using rainwater with domestic waterworks bacteria and germs may form in the pressure vessel when it is airtight. Using a washing machine under these conditions is also unadvisable. Alternatively, a submersible pressure pump could be used.
What other costs will there be after the initial purchase?
Good domestic waterworks require relatively little maintenance. In winter they should be free of frost and be emptied. Otherwise, in addition to the electricity costs for operation, only the costs for the membrane in the pressure vessel, which has to be replaced approximately every 2–3 years, need to be taken into account. Depending on the water quality, wells may require an additional iron filter, which usually only needs to be rinsed to be cleaned. Iron filters therefore require almost no maintenance. Experience shows that it makes little sense and would be a false economy to save on the purchase of domestic waterworks. If you decide to invest in a solid model, you will enjoy many years of reliable equipment.