Is Softened Water Corrosive?

No! The removal of hardness does not effect corrosion.

Water is an essential resource that we rely on for various purposes, including drinking, cooking and cleaning. However, the quality of water can vary depending on its source, and in some cases, it may contain minerals that can cause problems like limescale buildup in pipes and appliances. To combat this issue, many people turn to water softeners, which remove the mineral content to create softened water. While softened water has its benefits, there has been ongoing debate about whether it can potentially be corrosive. 

How does a water softener work?

Water softening involves the removal of "hardness minerals" such as calcium and magnesium ions, which are responsible for limescale formation. The process typically uses an ion exchange resin, which traps the calcium and magnesium ions and replaces them with sodium ions, resulting in softened water.

Doesn’t salty water cause corrosion?

Some people express concerns that softened water may be corrosive due to the increased sodium content. The idea is that the higher levels of these ions in softened water could lead to accelerated corrosion of metal pipes, fixtures, and appliances, potentially causing damage and increased maintenance costs.

What do studies actually show?

  • pH Levels: Softened water generally has a slightly elevated pH level due to the presence of sodium ions. This mildly alkaline will actually lessen corrosion to some extent as it creates a protective layer on the metal surfaces, hindering the progression of corrosion.
  • Reduced Hardness Minerals: By removing hardness minerals, water softeners also eliminate one of the primary catalysts for corrosion. The absence of calcium and magnesium ions decreases the potential for limescale buildup and reduces the likelihood of corrosion caused by these minerals.
  • Sodium Content: Although the increased sodium content in softened water may raise concerns, it is important to consider the concentration levels. In most cases, the amount of sodium added during water softening is not significant enough to cause significant corrosion issues. 

So is softened water corrosive?

After looking at all of the evidence above, it can be concluded that softened water, when properly treated, does not pose a significant risk of corrosion. While the slightly alkaline nature of softened water can provide a protective layer on metal surfaces, the absence of hardness minerals and the relatively low levels of sodium make it unlikely to cause extensive corrosion damage. However, as with any water treatment method, it is crucial to consider individual circumstances and consult professionals, such as your local AIWSE member when necessary.

Remember, if you have concerns about water quality or potential corrosion, it is best to consult with your local AIWSE member who can assess your specific situation and provide appropriate recommendations.

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Paul Webb

Has worked in water treatment, plumbing and construction throughout his career.
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