Cation Exchange Water Softeners

Hard water can make it difficult to rinse soap off and cause other issues. Cation exchange water softeners remove the calcium and magnesium ions found in hard water by exchanging them with sodium (or potassium) ions.  Water softeners can help protect appliances and make water more appealing to people who live in areas with hard water. However, water softeners can consume a significant amount of water and salt in the treatment process because the water softener undergoes a regeneration process to flush the system of excess ions and recharge with new sodium ions. While WaterSense does not label water softeners, EPA provides information to help consumers select water- and salt-efficient models and learn how to use and maintain these systems to minimize water waste. 

Water Softeners User Guide

WaterSense has developed a fact sheet and guide to help consumers understand how water softeners work, explain how to select a more water-efficient softener, and provide tips for softener use and maintenance. 

• Soften Water Without Wasting It: Water-Efficient Home Water Softeners (pdf) (274.6 KB, May 2026)
• Soften Water Without Wasting It: Guide to Selecting and Maintaining a Water-Efficient Water Softener (pdf) (1.47 MB, May 2026)

Water Softeners Specification

In November 2010, EPA released a notice of intent (NOI) to develop a draft specification for water-efficient softeners to earn the WaterSense label. The process of regeneration can use 25 gallons of water or more per day, or up to 10,000 gallons per year. Recent improvements in water softening technology demonstrated that there is a potential for water savings and WaterSense believed there was an opportunity to capitalize on this water savings opportunity, raise consumer awareness, and further improve the efficiency of water softeners. 

EPA ultimately decided not to proceed with the development of a draft labeling specification for softeners because it needed to further explore concerns raised by some stakeholders in regards to the effect of water softener discharge on wastewater treatment. WaterSense encourages interested parties to provide input on any of the issues presented in the NOI and will inform stakeholders if the program decides to move forward with a specification in the future. If you have comments or suggestions, please contact us at watersense-products@erg.com.

• Water Softener NOI (PDF)(8 pp, 56 K, About PDF) 
• January 19, 2011 meeting on the NOI
  • Water Softener NOI Meeting Summary (PDF) (14 pp, 136 K, About PDF)
  • Water Softener NOI Meeting Presentation (PDF) (28 pp, 220 K, About PDF)
  • Water Softener NOI Comments (as of July 2011) (PDF) (72 pp, 4 MB, About PDF)