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Road salt and water quality

dump truck spreading salt on snowy road

MPCA recommends a low-salt diet for Minnesota waters. Doctors tell us to stick to a low-salt diet. Our lakes and streams should follow the same advice. When winter comes and snow and ice build up on Minnesota roads, parking lots, and sidewalks, one of the most common reactions is to apply salt, which contains chloride, a water pollutant.

Salt pollutes. When snow and ice melts, the salt goes with it, washing into our lakes, streams, wetlands, and groundwater. It takes only one teaspoon of road salt to permanently pollute 5 gallons of water. Once in the water, there is no way to remove the chloride, and at high concentrations, chloride can harm fish and plant life. Less is more when it comes to applying road salt.


Wonder what we’re doing to address this important issue?

  • The MPCA partnered with local and state experts in the seven-county metro area.
  • Created a plan for effectively managing salt use to protect our water resources while maintaining public needs.

Review these documents and learn more:


In the news

Chloride and our water — monitoring the mix



Follow these simple tips to protect our water!

There are many ways to reduce salt use while maintaining high safety standards.

  • Shovel. The more snow and ice you remove manually, the less salt you will have to use and the more effective it can be. Whether you use a shovel, snow blower, snow plow, or ice scraper, get out there as early as you can and keep up with the storm. You may even decide that salt isn't needed.
  • 15°F is too cold for salt. Most salts stop working at this temperature. Use sand instead for traction, but remember that sand does not melt ice. Use the reference table below to apply the correct product for the conditions.
  • Slow down. Drive for the conditions and make sure to give plow drivers plenty of space to do their work.
  • Be patient. Just because you don't see salt on the road doesn't mean it hasn't been applied. These products take time to work.
  • More salt does not mean more melting. Use less than 4 pounds of salt per 1,000 square feet (an average parking space is about 150 square feet). One pound of salt is approximately a heaping 12-ounce coffee mug. Consider purchasing a hand-held spreader to help you apply a consistent amount.
  • Sweep up extra. If salt or sand is visible on dry pavement it is no longer doing any work and will be washed away. Use this salt or sand somewhere else or throw it away.
  • Watch a video. This video, produced by the Mississippi River Watershed Management Organization, provides tips to homeowners about more environmentally friendly snow and ice removal: Improved Winter Maintenance: Good Choices for Clean WaterExit to Web
  • Share a brochure. Read and pass along Nine Mile Creek Watershed District's brochure about residential snow and ice care: PDF Document Residential snow and ice care (Nine Mile Creek Watershed District) External Link
  • Check out other resources. If you are responsible for snow and ice removal somewhere other than your home, please check out our training and resources tab.

Know about the salt product

Salts can range from simple table salt to calcium chloride. Salts are used because they are able to decrease the freezing point of water. Whatever product you chose, make sure you know at what temperature it stops working. We recommend using the table below as labels may be misleading. Note that pavement temperatures are usually warmer than air temperatures. To find out the pavement temperature near you, search the Road Weather Information Service.

Melting agent

Lowest pavement temperature
at which product works

Calcium chloride (CaCl2)

-20° F

Potassium acetate (KAc)

-15° F

Magnesium chloride (MgCl2)

-10° F

Sodium chloride (NaCl)

15° F

Calcium magnesium acetate (CMA)

20° F


Check with manufacturer.


Never melts, provides traction only.

Environmental concerns

Environmental concerns about road salt

Road salt harms our environment

Road salt, a commonly used deicer, helps keeps our roads free from ice and safe for drivers. An estimated 365,000 tons of road salt is applied in the Twin Cities Metropolitan Area (TCMA) each year. The chloride in road salt flows into our lakes, streams, and groundwater and harms our environment. Water softening, industrial dischargers, and fertilizer also contribute chloride to surface waters. We have made a lot of progress in Minnesota, but there is still a lot of work to be done in order to keep our waters clean, while keeping our roads safe. This year the number of waterbodies that are impaired for chloride more than doubled. Currently, there are 21 lakes, 22 streams, and 4 wetlands that are impaired for chloride.

Once chloride is in water, the only known technology for its removal is reverse osmosis through massive filtration plants, which is not economically feasible. This means that chloride will continue to accumulate in the environment over time. A study by the University of Minnesota found that about 78% of salt applied in the TCMA for winter maintenance is either transported to groundwater or remains in the local lakes, and wetlands (Stefan et al. 2008).

Research identifies the negative impacts that chloride has on the environment, but there are still many unknowns. Continued research will help us understand how chloride interacts with the environment and therefore, how to protect our water resources.

What’s the problem with salt?

Drinking water

  • 75% of Minnesotans rely on groundwater for drinking water. High amounts of salt in groundwater cause drinking water to taste salty, which could restrict its use for drinking. The cost to remove salt from drinking water using reverse osmosis would be expensive.
  • Salt in drinking water is a health concern for people with high blood pressure, or hypertension.
  • Chloride can be naturally present in Minnesota's groundwater in varying amounts due to the weathering of rocks and varies greatly across the state. However, additional (non-natural) chloride also enters groundwater from deicing salt, fertilizer, water-softening salt, and septic systems.  
  • Groundwater flows into streams, lakes and wetlands. If the groundwater contains high amounts of chloride, the organisms that live in surface waters can be negatively affected.

The MPCA groundwater report found that:

  • 27% of monitoring wells in the TCMA in the sand and gravel aquifers had chloride concentrations that were greater than drinking water guidelines set by the EPA (250 mg/L), likely from winter de-icing chemicals.
  • 30% of wells in the TCMA had chloride concentrations greater than the chronic water quality standard (230 mg/L).
  • The source of high chloride concentrations in the TCMA and other urbanized areas is likely from salt applied for winter maintenance.
  • For more information check out the full report: PDF Document The Condition of Minnesota’s Groundwater, 2007-2011 (wq-am1-06) or the summary of key findings: PDF Document Summary (wq-swm1-01) .

Fish and aquatic bugs

  • High amounts of chloride are toxic to fish, aquatic bugs, and amphibians.
  • Chloride can negatively affect the fish and insect community structure, diversity and productivity, even at lower levels.>
  • Chloride changes the density of water, which can negatively affect the seasonal mixing of lake waters. Mixing increases oxygen levels required by aquatic life.


  • Direct deicing salt splash can kill plants and trees along the roadside.
  • Plants can also be harmed by taking up salty water directly through their roots.
  • When chloride flows into streams, lakes, and wetlands, it harms aquatic vegetation and can change the plant community structure.


  • Salt may cause soil to lose its ability to retain water, which could lead soil erosion. Increasing sediments going into surface waters can negatively impact aquatic organisms.
  • Excess salt can make soil more alkaline and compact, and less permeable, making it more difficult to store nutrients that plants need to grow.


  • Pets may consume de-icing materials by eating them directly, licking their paws, or by drinking snow melt and runoff, which can be harmful to pets.
  • Exposure to road salt can cause pets to experience painful irritation, inflammation and cracking of their feet pads.


  • Some birds, like finches and house sparrows, have an increased risk of death due to ingesting deicing salt.
  • Salt attracts wildlife to roadsides, where they can be hit by cars.
  • Deicing salt can cause a decline among populations of salt sensitive species, reducing natural diversity.


  • Chloride corrodes road surfaces and bridges and damages reinforcing rods, increasing maintenance and repair costs.
  • Deicing salt accelerates rusting, causing damage to vehicle parts such as brake linings, frames, bumpers.

Related links


For residents

Training video

Did you ever think about what happens to tons of salt that goes on our roads, parking lots, and sidewalks each winter? Most of it ends up in our lakes, streams, and wetlands. As a result, clean water in the Twin Cities is in jeopardy.

No salt, or very little salt, is needed if you've done a good job of snow removal. To learn a few easy things about tools, techniques, and products that you can use to keep your driveways and sidewalks safe while protecting our waters, watch this new video.

Improved Winter Maintenance: Good Choices for Clean Water (15 Minutes)

The MPCA gives special thanks to the Mississippi Watershed Management Organization for producing this video.


PDF Document Residential snow and ice care (Nine Mile Creek Watershed District) External Link


PDF Document Salt pollutes postcard (p-tr1-45) (tips on ways to reduce salt use). Print this postcard and distribute to residents and local businesses.


Changing our waters with salt February 1, 6:15-7:30 pm, Edina Public Library, Grandview Square. The event is sponsored by the Minnehaha Creek Watershed District, Minnesota Waters, 9 Mile Creek, and Citizens for Minnehaha Creek Corridor. For more information on the workshop, visit Nine Mile Watershed District's calendar page. Exit to Web

For building entrances and sidewalks

This 20-minute video will introduce you to best practices for maintaining small spaces (sidewalks, entryways, steps, etc) in the winter, including deicer material selection and application rates.

Training Video — Winter Maintenance Training for Small Sites

Part 1 (10 minutes)

Part 2 (10 minutes)

The MPCA give special thanks to the Mississippi Watershed Management Organization, the University of Minnesota, and Fortin Consulting for producing this video.

For property managers

How do I find a certified contractor?

If you hire out snow removal on your property, choose a contractor who is certified by the state in Snow and Ice Control Best Practices or encourage them to become certified.

Certified practitioners may found in the file below.

Why should I hire a certified contractor?

Many local lakes and streams have elevated levels of chloride, a common ingredient in road salt. In some cases, the chloride contamination is high enough to impact or even kill fish and other aquatic life. Winter snow and ice practices have been identified as the primary source of this chloride. Certified contractors have taken a training on how to mitigate the effects of de-icing materials on the environment, without compromising safety or effectiveness.

Voluntary certification in Snow and Ice Control Best Practices from the MPCA is given to individuals who:

  • Attended voluntary training
  • Complete and pass the associated test
  • Agree to voluntarily apply best management practices to reduce chloride impacts

Related links



Photo of snow removal and road salt application

In February 2005 a $25,000 grant was awarded to Fortin Consulting of Minneapolis. The purpose of this pollution prevention grant was to develop and test an education outreach program to local government and private applicators of road salt. The key objectives of the outreach were to:

  • develop best management practices (BMPs) for application of road salt;
  • develop a training program and conduct three pilot training sessions;
  • follow-up those trained to learn what changes occurred as a result of using best management practices, as summarized in the following report:

The target of this training is private applicators. However, other interested parties and local government officials are also being trained. In this way local officials will be knowledgeable about the training that is going on in their city, can learn the newest techniques, and be in a position to continue training in their city. Also, cities have the opportunity at these training sessions to address the audience and cover any other environmental concerns affecting lakes and streams.

For road maintenance staff

MPCA Level 1 Certification: Snow and ice control best practices

Through education and outreach, applicators of road salt can learn best practices and significantly reduce their use while maintaining road safety.

Who should participate? Contractors and staff maintaining private/public walkways and/or parking lots, Property managers writing contracts, distributors of anti-icing/de-icing products, snowplow drivers— those who make it happen.

Why Is it important? This class will help:

  • Save you money.
  • Keep our parking lots and sidewalks safe.
  • Protect our water.
  • Get you certified.

List of individuals certified

A voluntary certification was given to individuals who:

  1. Attended voluntary training;
  2. Completed and passed the associated test; and
  3. Agreed to voluntarily apply best management practices to reduce chloride impacts

The list of individuals given this voluntary certification to date is contained in the following document:

Please note: Individuals certified in Minnesota will have to re-certify once every five years.

Training schedule

Because of the initial success of the pilot project, Fortin Consulting has received a 319 grant to conduct additional training sessions in Minnesota. The following training schedule is changed periodically as training events are completed/added.

Maintenance manual and in-truck clip board

Winter Parking Lot and Sidewalk Maintenance Manual - CoverIn the Spring of 2006, additional P2 funds were provided to develop written materials to be used by applicators. Under this approach, a technical advisory group was formed to provide input into a winter maintenance manual. It was originally thought the manual would be compact in an effort to encourage applicators to have it available in their vehicle. After a number of meetings with the technical advisory group it was decided to split off key charts and information critical to have in a vehicle before, during and after winter storm events. This created a stand alone manual and two pages of charts/critical information (clip board pages).

  • PDF Document Winter Parking Lot and Sidewalk Maintenance Manual (p-tr1-10) (August 2015) — this manual will be used and handed out as a reference document during the training sessions. A copy of the manual will be given to each training participant as a take home reference document.
  • PDF Document Clip Board Pages  (p-tr1-20) (October 2010) - for applicators attending training will be given a clip board containing critical information. The hope is that this clip board will be a useful tool for applicators to keep in there vehicles during storm events.

Additional Winter Maintenance Resources


Sample Snow Policies

The Shakopee Mdewakanton Sioux Community Salt Management Plan

Pollution prevention (P2) case study from road salt training

De-icing chemicals applied to roadways can impair water quality and habitat, and are costly for local governments to purchase and to apply. Fortin Consulting and the Minnesota Local Technical Assistance Program provided a Minnesota Pollution Control Agency-sponsored winter maintenance training course for snowplow drivers in Dakota County Minnesota in November 2008. The goal was to improve operator effectiveness, and to reduce the amount of chemicals entering nearby water bodies. The Minnesota Pollution Control Agency (MPCA) and the University of Minnesota's Water Resources Center (WRC) partnered to evaluate the training through a KAP (knowledge, attitudes and practices) study. Beforehand a baseline was established. The study was repeated after two winter maintenance seasons and the results were compared. Fourteen months post-training, KAP results documented measureable improvements in driver knowledge, attitudes and practices related to specific application activities.

The study confirmed that the winter maintenance training fostered many changes. After Dakota County employees attended winter maintenance (road salt) training reductions in the use of chlorides were documented. For the 2008/2009 season the county used 14,175 tons of salt for thirty-five snow events, averaging 405 tons per event. For the 2009/2010 season the county used 9,585 tons of salt for twenty-seven events, averaging 355 tons per event. The correlates to about 40 million gallons of freshwater protected from chloride contamination per snow event.[1]  County staff attributed the decrease in salt from 405 to 355 tons to the use of computerized spreaders, the use of magnesium chloride, and to the winter maintenance training provided by Fortin Consulting in partnership with the MPCA. For detailed information concerning the P2 results of this study please refer to the following report:

Related links

TCMA Chloride Project

Metro Area Chloride Project

Chloride is a unique pollutant in that once it is in our waters there is no available technology to remove it and the primary source of chloride (road salt) is currently necessary for public safety; therefore preventing chloride from entering the environment and protecting waters from degradation while still providing public safety is critical to achieving the desired water quality.


The final outcomes of this project will be a chloride management plan which will lay out a strategy for addressing chloride impacts to our surface waters for the 7-county metropolitan area. This chloride management plan will satisfy EPA requirements for impaired waters, address waters not yet listed, and develop a strategy to protect waters that are currently meeting the water quality standards. This management plan will also include implementation activities for reducing chloride to TCMA waters as well as identify high priority areas to target implementation activities. The MPCA and the hired consultants will work with the inter-agency team, a technical advisory committee, a monitoring advisory team, and implementation plan committee and local stakeholders to develop this management plan to ensure that it is supported by our local partners and will result in ownership of the final plan.

TCMA chloride monitoring results

View Larger Map

Note: This map shows only waters that have been assessed for chloride by the MPCA in the 7-county metro area. Waterbodies without a colored label do not have chloride data available.

Stakeholder process

The MPCA project team will develop and execute a stakeholder process that facilitates positive interactions and ownership of the final restoration and protection plan recommendations and implementation efforts. The meetings will include identification of risks and opportunities, education on modeling and scientific data, and decision-making on preferred strategies and allocations. The diagram below shows the various teams that have been created (or will be created) to engage and participate in the project at various stages. A list of the members participating on each committee can be found below.

Interactions of the seven stakeholder groups

Inter-Agency Advisory Team: Provides high level oversight, support and guidance. Meets periodically Technical Advisory Committee: Provides review, guidance and support for the technical aspects of the project. Meets quarterly. Implementation Plan Committee: Provides guidance on the development of the implementation plan. Meets 2-3 times near the end of the project. Monitoring Sub-Committee: Subset of experts from the IAT and TAC. Provides detailed technical guidance and support regarding the water quality monitoring component of the project. Meets as needed. Outreach Group: Informal group, part of the audience that the MPCA will target to share project updates and information. Project Manager: MPCA staff who coordinates and leads this effort. Works with agency staff to meet the project needs and long term goals. Outreach & Education Committee: Consists of state and local education specialists.  Will assist with the development of “toolbox” for a broad outreach campaign for road salt education that can be utilized by local partners and road authorities.

Stakeholder process diagram

Project objectives

There are 10 tasks that have been created as part of a work plan for this effort. For a detailed description of each task, please refer to the complete project work plan available on the project website.

  • Task 1 Targeted chloride monitoring
  • Task 2 Update existing data compilation with recent data
  • Task 3 Categorize and define waterbodies for protection and restoration
  • Task 4 Develop target concentrations for non-impaired waters
  • Task 5 Source identification
  • Task 6 Modeling and analysis
  • Task 7 Develop Education/Outreach materials
  • Task 8 Write draft and final TCMA chloride management plan:
  • Task 9 Write draft and final implementation plan and long term monitoring plan
  • Task 10 Stakeholder process


The 10 tasks are on schedule to be completed within approximately 4 years. At the conclusion of the project, the state agencies and all local partners will have the information necessary to begin implementing practices to reduce the amount of chloride entering our waters.

Project Timeline

Project work products

For details on the project history including the Metro Chloride Feasibility study results, the partners involved, the process, and the detailed technical information, visit the project history page.

Other projects

Related links


All meeting information, including agendas, minutes, presentations, and electronic handouts can be found in PDF documents below. This document is bookmarked for ease in searching for specific meeting details.

Technical Advisory Committee meetings

  • July 1, 2014, 1:00-3:30 pm
  • April 23, 2014, 1:00-3:30 pm
  • December 12, 2013, 1:00-3:30pm
  • March 27, 2013, 9:30-12:00 pm
  • January 15, 2013, 9:30-11:30 am
  • October 12, 2011, 12-2:30 pm
  • September 8, 2010, 1-3 pm
  • PDF Document TAC meeting information (wq-iw11-06r)

Inter-Agency Advisory Team meetings

Monitoring Sub-Committee meetings

  • February 26, 2013, 1-3 pm
  • October 6, 2011, 9-11 am
  • March 3, 2011, 9-10:30 am
  • October 14, 2010, 1-2:30 pm

Education and Outreach Committee meetings

  • March 11, 2014, 10-12 pm
  • April 12, 2012, 9-12 pm
  • December 7, 2011, 1:30-4 pm
  • October 6, 2011, 1-3 pm
  • PDF Document EOC meeting information (wq-iw11-06y)

Implementation Plan Committee meetings

  • September 30, 2014, 9:00 a.m. - 12:00 p.m.
  • May 9, 2013, 8:45-12:30 pm
  • July 10, 2012, 8:30-1:00 pm
  • PDF Document IPC meeting information (wq-iw11-06z)

Outreach Group meetings

MPCA project team presenting at the following events/conferences:


Watershed Project Manager

Brooke Asleson
Minnesota Pollution Control Agency
520 Lafayette Road
St. Paul, MN 55155

Follow me on Twitter @brookeMPCA

Road Salt Education Program

Andrew Ronchak
Minnesota Pollution Control Agency
520 Lafayette Road
St. Paul, MN 55155

Last modified on November 13, 2015 16:27

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