Residential Softening and Chloride Discharge
According to a January 2019 report published by the University of Minnesota Water Resources Center, Minnesota Pollution Control Agency and University of Minnesota Dept. of Civil, Environmental and Geo-Engineering, high chloride levels in surface water and groundwater are an emerging concern in Minnesota, as they can negatively impact aquatic and plant life. Previous research has shown that road salt is a major source of chloride, particularly in urban areas. Chloride discharge from water softener use is considered another major source, although the report indicates that increasing efficiency of water softeners could be a viable strategy to manage chloride levels in wastewater and receiving waters.
Communities are starting to take notice of chloride discharge in order to become compliant with the Safe Drinking Water Act. Communities are applying for grants through the Drinking Water Revolving Fund to upgrade, replace water treatment plants. Many communities are telling residents that treatment plant renovations will result in soft water; some are urging residents to disconnect home softeners.
So just what is soft water? Instead of having a high concentration of magnesium and calcium like hard water does, soft water has a lower level of these elements, but a higher concentration of sodium. Soft water is defined by the national Water Quality Association as grains per gallon (gpg) in the table below. If you live in a community that advertises “soft” water at the tap, ask what the hardness level is and determine whether the result is as good as you would achieve with a water softener in the home.
Communities in Minnesota that are either looking at community treatment options or have already implemented them include:
- Alexandria – The city and county are working together on ideas to reduce chloride discharge from road salt and softeners.
- Marshall – Marshall is looking for funding for a project to reduce hardness from 35 gpg to 6 gpg, using soda ash and lime instead of salt.
- Morris – Morris has passed a revision to city code that prohibits “brine wastewater discharge produced from a water softener, unless the softener is verified to be on demand and properly calibrated.” Additional information is available here and on a flyer sent to Morris residents.
- Pipestone – Pipestone’s $16 million water treatment plant is on track to be completed this summer. It will reduce radiation and chlorides and the city says it will pre-soften water.
- St. Peter – After upgrading its treatment plant, St. Peter, through its consultant engineers, estimates reduction in chloride discharge of approximately 2,000 tons per year through discontinued use or turning down salt use settings on residential water softeners. A public campaign was conducted in St. Peter to ask residents to turn down or shut off softeners.
- Willmar – Willmar is looking for funding to upgrade its treatment plant not only to remove contaminants but also to “pre-soften” water before it reaches residential homes.
- Avon – The City of Avon is holding a public hearing June 27 to give the public an opportunity to talk with MPCA representatives about how the city will deal with chloride discharge into Spunk Creek.
The list of communities that will receive grants to upgrade or replace water treatment plants in the coming year will be announced this summer.
What can consumers do? Have your water conditioning dealer discuss options with you – optimizing your softener is a good place to start. Upgrade to a high efficiency softener that only regenerates when needed. Make sure your softener is working at peak performance so you are not wasting salt or water. By making a few small adjustments in your home, you can have a large impact on Minnesota lakes and rivers.