Salt Monitoring Initiatives
FOSC is conducting two Salt Monitoring initiatives to assess the impact of road/sidewalk salt on Sligo Creek and its tributaries (Long Branch, Wheaton Branch, Takoma Branch and others). You may have read about how the use of road salt in the winter is hurting our waterways and, because salt isn’t removed by water treatment facilities, is ultimately affecting our drinking water. The Water Quality Committee has started to do something about it…with your help!
I. FOSC SaltWatch Monitoring in the Sligo Creek watershed
The Winter 2024/25 Salt Monitoring season is underway. If you are interested in joining the Salt Monitoring team – as a weekly tester or an event tester (during and after weather events where salt was spread), please email [email protected] to get details and sign up.
As we found last season, salt levels get exceedingly high due to winter salting and brining.
For a summary of our findings for the 23/24 season, read on.
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The Long Branch graph, above, shows a typical salt "bump" from the storm in the first week of January. On Jan. 16th, the morning after region-wide salting was completed for the recent large storm, the chloride levels shot up and stayed up for 13 days straight, until Jan. 28th. |
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II. How to Report Excessive Salt on Roads, Parking Lots, Sidewalks in the Sligo Watershed
To help reduce the amount of salt entering Sligo Creek, report excessive road, parking lot or sidewalk salt "piles" (such as the piles shown in the photos at the bottom of the page) in the Sligo watershed.
For Montgomery County roads that are unnumbered, including roads and parking lots in Sligo Creek Park, please:
- Report it directly to the County by email, with a photo if possible, and the day, time, and location of the salt pile. In the web form comments, clearly state that you want salt removed, not added. Request that they get back to you about the actions the County took to clean up.
- Or, call 311 from within MoCo. A written request is always better but sometimes all you can manage is a phone call.
Prince George's County
For PG County unnumbered roads:
- call either 311 (if you're calling from within PG County) or the PG Report Snow Conditions line at 301-883-4748. Tell them you want salt removed and provide a precise location and details - cross street, at curb/in middle of the road/etc.
State-maintained (numbered) routes
Report excessive salt on state-maintained roads (Rt 29, Rt 97, Rt 410, etc.) through:
- the State Highway Administration (SHA) service webform. Select topic "Weather-Related"/ subtopic "Snow/Plowing/Salt". In the comments section, clearly state you are requesting that excessive salt be removed. Request that SHA send you a follow up report.
- Or call SHA at 301-513-7300.
Report to FOSC as well
For all excessive salt spotted, please also email FOSC at [email protected] with a photo if possible, and the day, time, and location of the salt pile, and where else you reported it. Many educational, residential, and other sites are not covered by the salt reporting systems we mention above. We will try to get excessive salt removed if you report it to us, wherever it is, and will urge more effective salting practices.
Thank you!
III. Data Reporting for salt testing results
Results for Sligo Creek and other local testing sites - Winter 21/22/23
In the Washington region overall, the Izaak Walton League reports that Salt Watch testing results from 2021/22 showed 34% of streams had chloride at levels considered toxic to wildlife, or 230 ppm. Across the eastern and midwest US, 18% tested at that level.
Along Sligo and Long Branch, the average chloride levels at 14 test sites ranged from 216 ppm to 507 ppm, though FOSC volunteers' data show individual readings as high as 860 ppm during winter of 21/22. In the 22/23 testing, readings ranged from 43 ppm at Three Oaks Drive on Jan 8, to 187 ppm at Maple Ave and at Elson St, both also on Jan 8th just before the storm. On average, the salt levels were significantly lower in 22/23 season due to fewer storm events and a lighter hand with salt spreading by the County than in 21/22.
IV. Advocate for Reduced Salt Use and Alternatives such as Brining of Roadways
Let County Executive Marc Elrich and Director of MCDOT Christopher Conklin know that you support brining of roadways. Brining is as effective as rock salt for deicing but, because of the way it is applied, uses ~60% less salt than a roadway treated with rock salt. It would help protect wildlife in the watershed and county-wide, and save money too.
Please view the letters that the FOSC Advocacy Committee has sent to MoCo DOT, the MD State DOT , and others on this issue, as well as their responses. We are continuing to follow up with these groups to press for better training, higher quality equipment standards for contract salt applicators, and other measures to reduce excessive salt use.

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A mega-salt application - unnecessary and damaging to the creek just downhill from this location.
The IWLA is providing the regular range test kits for the FOSC salt monitoring initiative. Thank you, IWLA!


Excessive salt piles at Dallas Ave near Sligo Creek
Large salt piles in a Dallas Ave intersection close to Sligo Creek. DOT removed them shortly after the FOSC Section Steward reported them.

A local salt pile, courtesy of J. Galella at UMD

Road salt sprinkled on snow-cleared roadway
FOSC Advocates for More Responsible Salting Practices on Roadways
FOSC again shared our strong concerns in late January, 2025 about the excessive salting in the watershed with the Montgomery County Dept. of Transportation, the Dept. of Environmental Protection, and the State Highway Admin, which maintains the numbered roadways (University Blvd, Colesville Rd, Georgia Ave, Piney Branch, etc.) The letters and the responses are posted under the Advocacy tab, Letters and Testimony page.
2024 MoCo DEP/WSSC
SaltWise Guidance
Be salt wise!
One mug of salt will treat a 20' driveway or 10 sidewalk squares

The FOSC Water Quality team has rounded up these three handy salt use resources:
- Ways to manage your use of salt this winter - the County's Department of Environmental Protection (DEP) has advice whether you're a resident, business or other organization.
- For the status of salting/brining in your area, see the Montgomery County Winter Storm Information Portal - shows MCDOT's latest storm management actions.
- The City of Takoma Park Public Works Dept - although there is some overlap with Montgomery County, the City of Takoma Park runs a separate salt management program.