Drinking Softened Water

A Chemspy reader sent me an email asking about the best way to fix their water softener.

Hi, I have a water softener. I met a local repair service, not affiliated with the manufacturer in any way, who can rebuild my broken unit with better quality after-market parts. Sounds like a good plan to me.

So far so good…the reader goes on…

The repair guy proposes to add some good quality resin to the tank to “top it up” if needed, and to add charcoal to the resin tank as well, as a filter enhancement. He claims the charcoal will get cleaned when the resin goes through the water softener’s normal recharge.

Again, sounds reasonable to me, although I suspect that the efficiency of a unit will depend on the quality of the components and presumably the actual fault and how that has been repaired. But, it was the final sentence of the email that made my heart skip a beat.

I only know charcoal filters as something you put inline, and replace before it poisons the drinker with its collected contaminants. Could the charcoal really be recharged and have the same useful lifetime the resin has?

Can you spot the potentially fatal flaw in what this Chemspy reader is doing with his water softener? I can and I’ve emailed him to tell him to cease and desist with immediate effect or suffer the consequences…your thoughts in the comments below would be appreciated.

Author: David Bradley

Freelance science journalist, author of Deceived Wisdom. Sharp-shooting photographer and wannabe rock god.

5 thoughts on “Drinking Softened Water”

  1. The trademark Brita uses exactly a mixture of ion exchange and charcoal and is widely used.

  2. Just quickly Rick, drinking hard water has beneficial effects on reducing the risk of cardiovascular disease because of the relatively higher levels of calcium and magnesium ions. I am going to dig out studies on the putatively harmful effects of ion-exchanged water though. It was always something, as a chemist, that we were advised not to do…but like you say, evidence would be good.

  3. I am not convinced that drinking water from an ion exchange softener is harmful. I have softened all of my water for over 30 years in this way to correct the extreme hardness from borehole water supplied by Severn Trent Water. There is a history of hypertension in my family and I have it, but my wife’s blood pressure is normal. I looked after elderly people for over ten years and none of them had any hypertension problems from drinking the softened water and definitely no premature deaths.
    Can anyone post clinical test results to back up the allegations that drinking softened water is harmful? Until then, I will continue to drink it!

  4. Alain, thanks for your detailed reponse. My concern wasn’t the aesthetics of his filtration setup but the fact that he’s drinking ion-exchanged water. It’s not for drinking, it has high levels of sodium and little calcium, long-term use could cause health problems.


  5. I think we are avoiding the main issue here: what’s in the water?

    How hard is his water? Is it necessary? Did he get his water tested? Where is the water coming from?

    Water softener has for purpose to remove hardness ions, like Calcium and Magnesium, and replaces it with Sodium or Potassium.

    Activated Carbon (or Charcoal) is used for more aesthetic reasons, such as removing the taste and smell of chlorine. But the main function of AC is to remove bacteria and viruses.

    I seriously don’t think it’s a good idea to have 2 different filtration media in the same tank. You can have a softener and activated filters in series but you shouldn’t have both media in the same filter tank. It is simply NOT DONE.

    My recommendation is to have 2 separate tanks for each filtration media and if possible, to have an automated backwash controller to help with maintenance.

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