Myth: Soft water is corrosive and bad for the pipes

Soft water It’s gentle on your pipes, just as it is on your skin. It would be rather odd if dermatologists recommended a water softener if you suffer from, say, eczema, but your pipes couldn’t cope with it.

So how did this myth come about? Quite simply, soft water is being confused with acidic water. Acidic water causes corrosion in your pipes, but soft water is not acidic. Soft water is neutral (pH between 7 and 8), just like hard water. The fact that the calcium and magnesium ions in softened water are replaced by sodium ions does not affect the acidity (pH-neutral).

Corrosive water is water that is slightly acidic and therefore not pH-neutral. Corrosive (acidic) water does cause damage to pipes (corrosion). Acidic water and water softening are not related.

See also:

Soft water removes existing limescale 

Does soft water damage copper pipes?