Water softening - what options are there?


There are many ways of reducing too high a degree of hardness of drinking water. Which methods are there, where they are used and where their advantages and disadvantages lie, is presented in this article. In addition, this article also answers the question of where water softening can make sense and what the risks to having soft water can be.

Water hardness categories

The water hardness can be divided into different categories. Softening is useful only for water in the "hard" category.

This category starts from a hardness of 14° dH. If the hardness is lower, there is a risk that the softening will make the water too soft. This can sometimes have disadvantages.

Rainwater does not need to be softened. It has a hardness of almost zero by nature, because it is not pressed by a mineral soil like the groundwater.

Purpose of water softening

A water softening can be done to prevent the precipitation of lime when heating the water. From a temperature of around 60° C precipitates in hard water lime.

The calcium crystals can then be deposited on heating rods, for example, but also in the boiler, and cause severe damage in a very short time due to calcification. With a kettle, the damage is still to get over, with washing machines and boilers repairs can be very expensive.

Another purpose for water softening may be to protect the pipes. There can also form deposits over time, when the drinking water is very hard. The deposits are similar to dolomite and virtually insoluble.

Also, faucets and sinks and the toilet can calcify hard water. But this can be remedied by frequent cleaning. When cleaning, acidic cleaners or special anti-limescale cleaners should be used to safely remove deposited limescale with each cleaning.

Lime is harmless in drinking water. In any case, both calcium and magnesium are minerals that we need to a great extent. The relatively low content in drinking water is even so low that it can be disregarded in nutritional planning even with very hard water.

Water softening by additives

Most detergents today already contain additives to prevent the precipitation of hardness agents.

Although the effect of surfactants in modern laundry detergents is no longer dependent on water hardness, most detergents still contain up to 30% additives for softening the water.

By preventing the precipitation of calcium and magnesium, the washing machine is protected in hard water. Only the consumption of detergent remains higher than with soft water.

It can alternatively be operated with rainwater - for such a service water system but a high installation cost is necessary. In addition, due to the softness of the rainwater, the risk of high foaming and insufficient rinsing.

Water softening through a central system

In order to protect the water pipes and the boiler, and to make frequent cleaning superfluous, a central water softening system can be installed. Here are several techniques available.

Ion exchange systems, which are also standard in dishwashers, extract the calcium and magnesium ions from the water and replace them with sodium. By exchanging the cations, the drinking water is softened and "salted up". But that has no harmful side effects.

After a period of time, ion exchangers must be regenerated. This is done with the help of a saline solution, which floats the retained Ca + and Mg + ions and recharges the exchanger element with sodium ions. The Ausschwemmwasser is useless.

A reverse osmosis system has a high energy consumption, but also offers opportunities to remove not only lime but also other undesirable substances from the water. It is thereby thoroughly cleaned again.

Although plants that work on a magnetic or electrophysical route are often praised as being highly effective, their effectiveness is poorly documented for many of these plant types.

In addition, these systems only remove the carbonate hardness from the water. The permanent water hardness is not reduced thereby.

There is no such thing as a "miracle cure" for softening water - many of the devices offered according to exotic principles of action do not work in practice, or only very poorly.

DVGW seal

The association for the gas and water sector assigns a test mark for all devices that have proven their effectiveness before an independent body, and can also be safely used for drinking water.

The test mark consists of a broken circle in gray, red and blue and bears the name "DVGW product" and the DIN mark.

Devices that are not labeled with this seal should always be examined critically. Especially if they allegedly include new and groundbreaking technology.

Tips & Tricks

In any case, before buying a system, ask what the real benefit is - and in which area. It often works without water softening system.


Video Board: What Are Your Water Softener Options?