Using soft water on hair has several different effects. The primary advantage is that hair becomes cleaner when washed in soft water. A major disadvantage, however, is that while the hair may technically be cleaner, it can appear lifeless and lack body. Whether water is classified as soft or hard mainly depends on what its measured calcium content is; basically, the higher the calcium content, the harder the water. Soft water tends to be found in places with low levels of limestone deposits or in residences where water softeners or filters are installed.
Water is classified as either soft or hard depending upon its calcium content, which is measured in parts per million. To be considered soft water, less than 160 parts per million of calcium must be present. For slightly hard water, the acceptable range is 160 to 320 parts per million, and anything over 460 parts per million is considered very hard. In addition to calcium, other minerals such as magnesium and manganese are also present in hard water, although in minimal amounts. The calcium content in water naturally rises wherever significant amounts of limestone are found in the ground.
When it comes to washing hair, the hardness of the water has a big impact on how well certain cleaning agents work. Natural soaps, such as Castile soap, tend to leave a residue behind after washing that makes the hair look stringy and greasy when washed in hard water. Under these circumstances, using soft water on hair proves superior, as all residue is easily rinsed away. The problem is that many people don't have access to soft water, so manufacturers had to come up with alternative cleaning agents, such as sodium lauryl sulfate, to make their products react well under hard water conditions. Otherwise, the only options available would be to purchase water softeners or shower filters to soften the hard water so it would clean more effectively.
Despite having better cleaning properties, using soft water on hair has its drawbacks. Putting the effects of cleaning agents aside, using soft water on hair tends to make it appear flat and lifeless. While using soft water on hair is helpful in washing away unwanted residue and buildup, factors such as shine and body tend to be sacrificed. To combat this, people using soft water often end up using volumizing styling products to give their hair additional body and bounce. Whether people prefer using soft or hard water will depend on personal preferences and what they're used to.
