What is the chemical composition of soft water?

Skład chemiczny miękkiej wody

The water that flows through our pipes and faucets is not the same in every region. One of the basic parameters that differentiate water is its hardness, i.e. the content of calcium and magnesium ions. But what exactly does the term "soft water" mean and what is its chemical composition? We answer these questions in the article below.

What is soft water?

Soft water is water that contains small amounts of calcium (Ca²⁺) and magnesium (Mg²⁺) ions. This usually means that its hardness is less than 60 mg/l expressed as calcium. In practice, soft water is more "pure" than hard water in terms of these ions, which affects its chemical and physical properties.

Chemical composition of soft water

In addition to calcium and magnesium ions, water contains various other ions and molecules such as sodium (Na⁺), potassium (K⁺), chloride (Cl⁻), sulfate (SO₄²⁻), etc. In soft water, the amount of calcium and magnesium ions is much lower, but this does not mean that they are completely absent.

The role of calcium and magnesium ions

Calcium and magnesium ions, although in smaller amounts, are still present in soft water and still perform certain biological functions. For example, magnesium ions are essential for the proper functioning of the nervous and muscular systems, while calcium is crucial for the health of bones and teeth.

Other substances in soft water

Please note that soft water may also contain other substances such as heavy metals and organic contaminants, depending on its source and the treatment processes it has gone through.


Understanding the chemical composition of soft water is crucial to its proper use, both in the home and in industry. Although soft water is generally devoid of major amounts of calcium and magnesium ions, it may still contain other important chemicals that affect its quality and use.

See also:

Have a question? Write!


Don't know what to choose? call!

So many water softeners on the market that you don't know what to choose? You do not want to overpay for expensive advertising campaigns for water softeners, but at the same time you are looking for an effective solution? I am here to help you! I will find matching equipment for your needs.

Phone: (+48) 532 916 941