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Water Softener Topic 13: Understanding Potassium or Sodium use in salt water softener

Recently one of the community members asked about what is the difference in using potassium vs sodium in water softener. This is a bit loaded question. So, thought of responding to this in detail so that broader members could benefit from this (those who are on look out for such information) post. I will try to answer this based on my knowledge. Even before I go into the details, would like to mention that both Sodium and Potassium are very efficient at the removal of hardness (calcium, magnesium and ferrous iron) from the water and they do really well and follow the same concept of ion exchange for the removal of hardness (calcium, magnesium and ferrous iron).

General points (not necessarily mine) for considering using potassium in water softener’s are;

1. To potentially avoid excess intake of sodium

2. Presence of potassium in softened water acts as dietary supplement

3. Potassium is good for watering plant

4. Drained water from softener is not good for the environment

Points against use of potassium in water softener’s are;

1. It is nearly 4-6 times expensive than sodium (40 lb bag)

2. Potassium sticks to the surface of resin tank more strongly than sodium and hence requires settings for the salt consumption approx. 10% higher than sodium

Below is the publication from W.H.O regarding the use of the potassium in water softener systems.

“The move to using potassium is driven by concerns over the total dietary intake of sodium, particularly in developed countries where there are concerns regarding the high intake of salt from processed foods. In contrast, there are also concerns that some diets may be low in potassium. This is not a concern for the general population ”The above statement is very important and key thing to note is “This is not a concern for the general population”

That said for certain high risk category of population

“increased exposure to potassium could result in significant health effects in people with kidney disease or other conditions, such as heart disease, coronary artery disease, hypertension, diabetes, adrenal insufficiency, pre-existing hyperkalaemia, older individuals who have reduced physiological reserves in their renal function and/or individuals who are taking medications that interfere with the normal handling of potassium in the body. Infants also have a limited renal reserve and immature kidney function and may therefore be more vulnerable.”

Here is a publication from W.H.O on use of sodium in water softeners;

There are few other studies alluding to the linkage of sodium to some health impacts as well. In my opinion, it is better to consult your own doctor for your specific situation (if you fall under any of the high risk categories or category sensitive to sodium). In their conclusion section of the study, W.H.O mentioned below.

"Sodium salts are found in virtually all food (the main source of daily exposure) and drinking water. Sodium levels in the latter are typically less than 20 mg/litre but can markedly exceed this in some countries. On the basis of existing data, no firm conclusions can be drawn concerning the possible association between sodium in drinking-water and the occurrence of hypertension. No health-based guideline value is therefore proposed. However, sodium may affect the taste of drinking-water at levels above about 200 mg/litre."

1. From the above we know that regardless of potassium or sodium , for general population both do not pose any significant health risks and business is as usual 😊 It is only for the high risk category of people i.,e who are sensitive to either of these due to excess consumption, there may needs to be a mitigation plan recommended by their doctor and executed by a water quality expert with right kind of systems. But again, we are talking about really exceptions here.

In my personal opinion, even a smallest thing that potentially could impact someone is over amplified & generalized. That I think is how marketing thrives either in introducing new products or selling products or creating demand!

2. If for anyone either of them is a concern, an under-sink RO unit could remove both of them (and many other dissolved solids) to give out purest water for drinking and cooking. Again, there are several options and preferences here. But generally speaking, for those this is a concern this could be addressed or mitigated.

3. Potassium is abundantly present in vegetables, drinking water and almost in many sources that we consume. So, I am not particularly sure, using the potassium in softener will fill the gap as potential dietary supplement. In theory yes. But practically, most of us will be getting much more than what we need.

4. In my opinion is a bad idea to use softened water (either using potassium or sodium) for irrigation purposes as softened water is not the intended use case for such purposes. A better option is to create a bypass system or separation of water lines so that softened water can be used inside the home to protect plumbing, appliances and to provide other benefits and use the city water for the irrigation.

5. Most cities also require that the drain water from the salt based (sodium or potassium) systems is connected to the proper drain (drain that goes to sewer). While some tend to think they could use this drain water for irrigation purposes, unfortunately, the drain from softening system contains excess concentration of calcium, magnesium and ferrous as this is what the softener is meant to remove 😊 and hence most cities require that softener drain be connected in such a way that it goes into sewer system.

I penned a post on “Understanding importance of softener system's salt efficiency rating” here;

Water Softener 10/11: Understanding importance of salt efficiency rating (

This talks in detail about the California salt efficiency law for salt-based softeners, WQF (Water quality foundation study) and how drain water from softeners impact + ly/ - ly sewer system and why choosing a softener that meets or exceeds California salt efficiency standard is important in helping environment.

So there you go 😊

Bottom-line: Avoid trap of overthinking as use of both sodium or potassium does remove the hardness equally and really well. Use of either of them does not have any impact on the removal of hardness for which you are actually considering purchasing softener 😊. For general population neither of them seems to be a health or environmental concern (as long as they choose correct one). If you fall under category where you are sensitive to any of these, please consult your doctor and work with a water quality expert to design a system that best works for your specific medical needs rather than researching on internet. Again this category is more of an exception. Good news is, most salt based softeners support use of sodium as well as potassium. However, if you do not want to deal with any of these, go with salt less conditioners (which technically are not softeners). Good luck and go easy and enjoy the softened water or conditioned water whichever best works for you based on your thinking. Cheers!

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