Optimal water hardness

What is hard water, and is there an optimal water hardness for household use? In this magazine article, you'll learn what the term water hardness means and get an overview of water hardness in different German states. We'll also inform you about the disadvantages of excessively hard water. You'll also receive a guideline for the optimal water hardness and learn how to achieve it.

What is hard water?

Hard water is water that has a high calcium and magnesium content. Hard water also usually contains traces of strontium and barium. Limescale, in particular, is easily recognizable in your water. Pour water into a pot, bring it to a boil, then remove it from the heat, and you'll see small, stone-like particles at the bottom of the pot. This is the limescale that is normally dissolved in your drinking water.

Classification of water hardness

Depending on the region you live in, your water will have varying degrees of hardness. Since its amendment in 2007, the Detergents and Cleaning Products Act has divided water hardness into three grades: Soft hardness range = less than 1.5 millimoles of calcium carbonate per liter (equivalent to 8.4 °dH) Medium hardness range = 1.5 to 2.5 millimoles of calcium carbonate per liter (equivalent to 8.4 to 14 °dH) Hard hardness range = more than 2.5 millimoles of calcium carbonate per liter (equivalent to more than 14 °dH) The abbreviation °dH stands for German hardness. The previously applicable category "very hard" was removed with the 2007 reform of the hardness categories and included in the "hard" category.

Overview of water hardness in your state:

Of course, the water hardness in different cities and regions can vary from the values listed below.

The following list is intended to give a rough guideline as to the average water hardness to be expected in your state:

Brandenburg: 17.00 °dH
Berlin: 18.00 °dH
Baden-Württemberg: 15.00 °dH
Bavaria: 17.00 °dH
Bremen: 8.00 °dH
Hesse: 16.00 °dH
Hamburg: 16.00 °dH
Mecklenburg-Western Pomerania: 20.00 °dH
Lower Saxony: 14.00 °dH
North Rhine-Westphalia: 14.00 °dH
Rhineland-Palatinate: 15.00 °dH
Schleswig-Holstein: 13.00 °dH
Saarland: 10.00 °dH
Saxony: 11.00 °dH
Saxony-Anhalt: 22.00 °dH
Thuringia: 15.00 °dH



Does hard water harm the environment?

The answer to this question is a resounding yes. Hard water requires up to 100 percent more detergent, shower gel, shampoo, and soap. This naturally ends up back in the environment with your wastewater. It's important to note that waterworks are unable to completely filter all detergent residues from your wastewater. In addition, using hard water also increases your electricity consumption, as every millimeter of limescale requires up to 10% more energy.

What are the benefits of soft water?

As mentioned in the paragraph above, with softened water you use significantly less detergent, shower gel, soap, shampoo, cleaning products, etc. This saves you money. Furthermore, limescale residue can't build up in the kitchen, bathroom, windows, etc. This also saves you time when cleaning. Your laundry will also be noticeably softer and fluffier. The dishwasher requires no or very little salt. Your water pipes and water-using appliances will no longer build up limescale, thus saving you on electricity costs. Your skin will also feel much softer after showering.

Are there any disadvantages to soft water?

Using fully softened water, i.e., water with a hardness of 0 °dH, can also have disadvantages. Soaps may not dissolve as easily, and detergents may foam up too much. Therefore, it's important to adjust the water hardness to the optimal level.

What is the optimal water hardness?

As described above, neither too soft nor too hard water is ideal. The optimal water hardness is around 8.3–8.4 °dH. This ensures sufficient solubility of soaps. At the same time, your machines are protected and limescale stains are virtually impossible to form.

How can you as a consumer get the optimal water hardness?

To achieve the optimal water hardness, you can purchase a water softener. These systems can be installed on your domestic water supply with very little effort. Retrofitting the system is also straightforward. A good water softener has a valve that allows you to set the optimal water hardness. We recommend using a system without electronics. This way, you don't have to deal with tedious programming. Furthermore, the installation is very easy and you eliminate potential sources of danger.

Measure pH value

If you want to check your water quality, you're probably already familiar with terms like TDS meters, PPM levels, and microsiemens. These values provide information about the amount of dissolved salts and metals in the water. But another important metric should be on your radar: pH.

What is pH and why is it important?

The pH value measures the concentration of hydrogen ions (H⁺) in a liquid. It indicates how acidic or basic (alkaline) the water is. The scale ranges from 0 to 14:

0 to below 7: sour
7: neutral (like pure water)
over 7 to 14: basic (alkaline)

The lower the pH, the more acidic the water, and the higher, the more alkaline. A pH between 6.5 and 8.5 is ideal for drinking water. If the value is outside this range, it could indicate problems such as corrosion in the pipes or other contaminants.

The litmus test

One of the oldest and simplest methods for determining pH is the litmus test. Litmus is a natural pigment from lichens that changes color depending on acidity or alkalinity:

When it comes into contact with acidic water, it turns red.

In alkaline water it turns blue.

Litmus was once used for coloring, but today it is primarily known as an acid-base indicator.
There are two types of litmus tests:

Litmus tincture: Liquid dye that is added directly to water.

Litmus paper: Strips of paper soaked in the tincture and immersed in water.

Both variants are well suited to determine the pH value quickly and easily.

Indicator test strips – the practical solution for home
Indicator test strips are ideal for quick and comprehensive water analysis. These small strips contain multiple indicators and display various values after just a few seconds:

• PH value
• Water hardness
• Chlorine content
• iron
• Nitrate and nitrite
  

alkalinity

This allows you to monitor various quality parameters of your water with just one test. It's incredibly easy to use: Dip the test strip into the water, wait a moment, read the color, and you're done! These test kits are available for just a few euros and are ideal for regularly checking the quality of your drinking water.

Conclusion:
The pH value is an essential parameter for assessing water quality. You can measure it quickly and easily yourself using simple tools like litmus paper or indicator test strips. This way, you can always keep track of the quality of your drinking water – for greater safety and well-being in your everyday life.