The water free from salts of Calcium and Magnesium is called soft water.
It gives lather with soap.
It is suitable to use for drinking, cooking, etc.
Since soft water contains low amounts of minerals such as Magnesium and Calcium as compared to hard water, hence it does not contain excess minerals, and it does not cause potential health effects such as cardiovascular disease, diabetes, etc. hence soft water is safe for drinking purposes.