We moved into our house last summer. The water in our area is pretty hard, so we have a water softener for the house. The water softener has an impeller attached to it to meter the water and regenerate after a certain amount of water is used. Our furnace also has a humidifier attached to it, which is fed by post-water-softener water.

After the weather started getting cold last year, we turned on the humidifier. We then started having problems with our water softener - it was being used up before it was time to regenerate. After a few weeks I realized the humidifier might be at fault and shut it off. The water softener problem went away.

I suspect that the trickle of water used by the softener was not enough to turn the impeller attached to the softener, and over the course of multiple days might have consumed numerous gallons of softened water (I'm not sure how much the humidifier actually uses).

So, the questions:

  • Could this indeed be the problem?
  • Is there a solution for this?
  • Could there possibly be another cause?

I could move the water source for the humidifier to be before the water softener, but then the humidifier may get gunked up over time. However, the softener water seemed to crust up the humidifier's insert with salt, so ...

I should also mention that about a month ago we had to have the stuff inside the softener changed and the valve overhauled - it hadn't had maintenance for probably 15 years. The impeller would be this old, too.

  • try turning it back on see if since the rebuild it uses as much, if it starts using more like last time you just need to adjust your flush or regen cycle, some units tell you what the life of charge is check it prior to the cycle being done and if needed shorten your regen cycle
    – Ed Beal
    Nov 19, 2015 at 0:33
  • @EdBeal The softener can support the number of gallons it's set to. Only, not so with the humidifier on. I suppose we could set the softener to regen more often, but when the humidifier isn't running, it would be regenerating early - there's not much control then, if my hunch is right.
    – Steve
    Nov 19, 2015 at 0:56

2 Answers 2


I think you've hit it on the nail. The humidifier takes a slow trickle of water, too slow to turn that impeller. This leaves the softener thinking no water is being used, when actually lots of water (over time) is being used. Eventually the media becomes saturated long before the softener decides to regenerate it.

Ion-exchange water softeners absorb calcium and magnesium and replace it with sodium. So, it seems likely that your humidifier will get gunked up no matter which side of the softener you connect it.

Edit: Is there a way to externally and electrically trigger a softener recycle? If so, then perhaps you can have a timer driven by the humidifier that, once every other day of humidifier runtime, triggers a recycle. Make sure that the softener does NOT perpetually recycle if the timer stops at just the wrong moment.


The humidifier doesn't care whether the water is softened. The softener just substitutes one mineral for another. Regardless of which minerals are in the water, there will be the same amount of it, and it will be left behind when the water evaporates in the humidifier. So you aren't gaining anything by sending softened water to the humidifier.

Doing this is, at a minimum, wasting the media, and it appears it is also messing up the softener.

There's no reason to "redesign" the softener to fix the problem, because there is no reason to feed the humidifier from it. Just move the humidifier feed so that the humidifier uses the unsoftened water.

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