Water categories

There are many type of waters and they are categorized  based on substances contain in water.  Here, we would like to focus on “normal water” – which the water plant provides to us and is justified as “not harmful” by the government. However, please keep in mind that this “normal water” still contains several subtances such as iron (Fe), magnesium (Mg), calcium (Ca), etc….

At professional laundry company, the “normal water” is not qualified and cannot be used. Professional laundry service divides water into 2 categories: hard water (or normal water) and soft water

1. Hard water

Water is categorised as hard if it contains a high concentration of calcium and magnesium

A degree of “hardness” depends on the level of calcium and magnesium exist in water. The greater amount of calcium and magnesium, the harder the water is.

Note: As hard water restrain washing powder’s effectiveness, it has a reverse relationship with washing quality

Water hardness is measured by  grains per gallon (gpg) or part per million (ppm)

  Grain per Gallon (gdg) Part per Millons (pmp)
Soft 0 – 3.5 0 – 60
Medium 3.6 – 7 61 – 120
Hard 7.1 – 10.5 121 – 180
Very hard Greater than 10.5 Greater than 180

2. Soft water

Soft water is an output of hard water after processed. Soft water contain calcium and magnesium smaller than 3.5 gdg or 60 ppm. Using soft water can improve washing quality

How to soften hard water 

There are several methods to soften hard water. Here, we will inform you the 2 simple methods to do it.

Option 1: Boil water 

By boiling water, we can reduce the hardness of hard water


  • As washing machine uses a lot of water, using hot water everyday is costly and takes time

Option 2: Use Ion exchange system

Source: Internet


  • High investment cost
  • Require frequent maintenance

Water and its influence on washing quality

Water is the main material in laundry. It is a solvent to dissolve washing powder and pick up impurities easily. However, if using hard water in a long time, your clothes will eventually change its original color to be yellowed (for white shirt) or to darken it

For the best washing quality and to prolong your items, we suggest to use soft water.