The Recovering Mill Creek



The Mill Creek, once named the most endangered urban stream in America, is on its way toward recovery.




Visit our interactive Mill Creek Water Quality Story Map  to learn more about the Mill Creek in a visual format.





MSD monitors water quality and aquatic habit in the Mill Creek, Little Miami River, and Muddy Creek every five years, partnering with the Midwest Biodiversity Institute (MBI) to perform comprehensive biological, chemical, and physical sampling and analysis.


A benchmarking (baseline) round of sampling in the Mill Creek was conducted in 2011-2014. A second round of sampling was conducted in 2016-2019. A third round of water quality sampling began in summer 2021 and will continue through 2023.


Please see the water quality reports for the Mill Creek below:




staff member from the Midwest Biodiversity Institute holding a black redhorse caught in the Mill Creek via electrofishing
Black redhorse in the Mill Creek at MC80 location. Note: This fish was caught by electrofishing and then released.


Video: Mill Creek - On a Journey Toward Recovery


Here are the highlights from the most recent (2021) water quality study of the Mill Creek:


  • Continued improvements between 2016 and 2021, and significant improvements since 2011.
  • 8 of 11 MWH sampling sites in the lower Mill Creek are in full attainment of their Aquatic Life Status. 20 out of 30 WWH sites in the upper Mill Creek are in full or partial attainment.
  • Exceptional macroinvertebrate scores were recorded in Mill Creek for the first time.
  • Chlorides and total dissolved solids continue to impact the Mill Creek.
  • E. coli counts are going down, but no site met the standards for wading or swimming (Primary Contact Recreation criteria).
  • 61 different species of fish found in the Mill Creek, with 7 new species, including smallmouth redhorse for the first time.
  • Species that are sensitive to pollution are now being observed in the Mill Creek, such as striped shiner, silverjaw minnow, and orangethroat darter.

MSD hosted a public Water Quality Forum on December 8, 2022, to present the results of the 2021 water quality study. For more information, please view the resources below:

2022 Water Quality Forum Presentation

2022 Water Quality Forum Handouts

2022 Water Quality Forum - Recording of Meeting (2 hours)



Mill Creek Yacht Club members canoeing on the Mill Creek
MBI electrofishing on the Mill Creek.