In one year, the Madison Metropolitan Sewerage District’s Nine Springs Wastewater Treatment plant receives 80 million pounds of salt from dissolved sodium chloride. Every day, that’s more salt than this pile! These dissolved particles pass through our wastewater treatment plant to local streams, exposing Wisconsin’s freshwater animals and plants to danger.
Freshwater organisms cannot tolerate high levels of dissolved solids such as chloride. Approximately 60% of the salt that we use and flush is the chloride ion. Scientists tested a variety of organisms and determined that a long-term exposure to chloride concentration of 395 mg/l is dangerous for the living organisms in the stream — a concentration equal to about half of a tablespoon of salt in five gallons of water. The wastewater that reaches our facility contains higher concentrations, created from various sources such as water softening systems, industrial sources and winter ice control. Chloride FAQ - Learn More.
Why should we Change?
While it only costs 20 cents to add a pound of salt to water, it costs five dollars to remove it. MMSD undertook a study which showed it could cost from $300-million to $2.3-billion to remove the required amount of chloride.
Rather than adding costly treatment in order to continue protecting our freshwater life, we have other options. Together, we can take small but helpful steps in order to reduce the amount of salt put into water by examining our current water practices. By understanding where this salt comes from, we can all identify and form habits that help maintain healthy waterways without sacrificing our well-being.
What Can We Do?
Look to Your Water Softener
An estimated 100,000 water softeners are tributary to MMSD’s Nine Springs Wastewater Treatment Plant, delivering more than half of the chloride passing through daily. The following steps can decrease your home water softener’s salt output:
- Optimize your water softener (our household softening study found that, on average, this can reduce salt use by 27%). Local water quality professionals provide this service.
- Replace older or inefficient softeners - the abovementioned study found on average, a 48% savings on the amount of salt used in a home by replacing an older softener with a new high efficiency softener. Timer based softeners (which regenerate after a certain time period vs. gallons used or hardness readings) have not been allowed by Wisconsin’s plumbing code for over 15-years because they are particularly wastefull of salt and water- if you have one, look into replacing it!
- If you’re in the market for a new water softener, look for a dual tank system and/or a softener that exceeds 4000 grains of hardness removed per pound of salt used. MMSD has worked with our local water quality professionals to develop a list of Best Practices to help you get an efficient new softener.
- View the District's home salt reduction brochure and share it with your contacts.
Modify Business/Industrial Practices
Large buildings like apartments, hotels, schools, factories and other commercial/industrial facilities can use a significant amount of salt, particularly for systems like laundry, heating/cooling and industrial processes. Updating your soft water system will not only reduce the amount of salt that flows to MMSD’s plant, but it could additionally save you money on your operations. In addition, we are offering grant programs to help you!
For information about salt reduction options and case studies of facilities that have successfully reduced their salt use, visit our salt reduction resources page, intended for large commercial/industrial/institutional facilities.
If you are interested in reducing your facility's salt use and would like more information about potential salt reduction projects or how MMSD rebates can apply to those projects, contact one of the MMSD staff listed to the right.
Be WI Salt Wise! - Adopt Water and Winter- Friendly Procedures
Chlorides are an issue for all local waters, including groundwater, drinking water, lakes and rivers. The health of our waters needs to be considered along with Wisconsin residents’ desire to have dry roads, dry parking lots and dry sidewalks immediately after winter storm events.
Let's work to protect our water resources by employing effective winter maintenance methods to avoid the over-use of road salt products. Remove the snow first, use the correct tools, prevent compaction, understand the size of the area you’re working with and most importantly, use the correct amount of salt (cups are available). For more information on how you can help Wisconsin’s waters, visit WiSaltWise.com: