The skinny on water softeners

Man filling water softener with saltA lot of us have experience with hard water’s unpleasant effects: dingy clothes, deposits on glassware and cooking utensils, scale buildup in pipes and on fixtures, and more. It’s not surprising that water softeners are a popular household item.

Soft water has some notable benefits. Among others, it can extend the life and improve the efficiency of water heaters, dishwashers, and other appliances, which potentially saves on water, energy, and detergent use.

A major drawback of salt-based ion-exchange water softeners is the chloride they produce and discharge into septic or sewage systems. Chloride from salt can seep into and pollute groundwater from on-site septic systems. Chloride also enters the environment via wastewater treatment facilities. Because facilities aren’t designed to remove it, chloride ends up in rivers, lakes and streams. High levels of chloride in the environment are toxic to fish and aquatic creatures.

Softening your options

If you own a water softener or are thinking of getting one, read on for some strategies that can help lessen their environmental impacts.

Degree of

Calcium carbonate:
Milligrams per liter

Calcium carbonate:
Grains per gallon
Soft 0 - 60 0 - 3.5
Moderately hard 60 - 120 3.5 - 7
Hard 120-180 7 - 10.5
Very hard More than 180 More than 10.5

Determine if you really need one­. Hardness is determined by the level of minerals, principally calcium and magnesium, contained in water – the more minerals present, the harder the water. Groundwater is typically harder than river or lake water. The table to the right provides a common classification of water hardness. You can purchase a hardness-testing kit, if you can access water that has not gone through a softener (perhaps from an outdoor tap). 

Before buying a softener, have your water tested for hardness or ask your city for information. Find out from your water utility if softening happens during the drinking water treatment phase. Minneapolis, St. Paul, Bloomington, and several other Minnesota cities use lime-softening or other upfront methods to soften their water, which eliminates or decreases the need for household treatment.

Reduce the salt. Only soften the water that needs it. Don’t soften water to outside spigots or to cold drinking water taps. Only soften to the optimal hardness – over-softening wastes salt and water and results in excess chloride. Check your unit's settings and adjust if they're too high – the equipment may have been preset at an unnecessarily high level at the factory.

Do things to reduce your overall water use. It will have environmental and economic benefits, including less need for water softening. Find ideas on how you can conserve water.

Adjust the timer. If you’re using less water because of changes in household size or because you’ve installed water-efficient appliances and fixtures—and your water softener is on a timer—you may be able to extend the time between regeneration cycles. Less regeneration results in less chloride in wastewater.

Upgrade to a high-efficiency water softener. If you're buying or upgrading to a new water softener (a good idea if you own an older unit), look for one that is high salt-efficiency and demand-initiated. Though you may pay a little more upfront, you'll save on salt and generate less chloride.

Go with a service. Another option is to subscribe to an exchange service. The company delivers soft water exchange tanks to the customer on a schedule determined by household size and water hardness level. Removed tanks are regenerated at a special facility, taking the handling of salt and solution discharge out of consumers’ hands.

Learn more

  • Chloride and water quality. In-depth information on chloride and water quality in Minnesota. Includes policy proposal from the Chloride Working Group.
  • Home water softening: Frequently asked questions. Collaboration between MDH and MPCA to show advantages and disadvantages of residential water softeners. 
  • Residential water softening. Information on how in-home water softening is affecting Minnesota's lakes and streams and resources for evaluating residential softening (Water Resources Center, University of Minnesota)
  • A recent article in the Pipestone County Star describe the city's plan to begin softening water at the drinking water plant, which will reduce or eliminate the need for home water softeners.
  • Water softener facts, Region of Waterloo and City of Guelph. Canadian government website contains useful information on how water softeners work, what to look for when shopping for one, water softener alternatives, and more.
  • Water hardness fact sheet. Brief, informative overview of water hardness and water softeners (Washington County Department of Public Health and Environment)
  • The effects of chloride from waste water on the environment, Center for Small Towns, University of Minnesota, Morris. 2013 report discusses the links between home water softeners and chloride pollution in the Pomme de Terre River watershed.