Louis L. McMahon

Widely recognized for his experience advising clients on complex Clean Water Act matters, Lou has extensive experience in all aspects of environmental law and related litigation. Lou’s experience includes brownfields redevelopment, CERCLA litigation, alternative energy as well as negotiation and appeals of National Pollution Discharge Elimination System (NPDES) permit renewals and modifications, surface and groundwater issues, wastewater issues, consent decrees, the Great Lakes and related public trust issues, and other environmental regulatory and legislative matters.

Lou frequently advises local governments regarding US EPA compliance and integrated planning of capital investments with other community objectives, including with respect to affordability and integrated planning aspects of Wet Weather Improvement Plans. He frequently negotiates federal consent decrees and consent decree modifications and represents sewer districts serving some of Ohio’s largest cities in negotiations with US EPA and Ohio EPA with over $6.5 billion of consent decree commitments.

Other experience highlights include:

• Defending a county and several municipalities from US EPA’s attempt to impose administrative orders for sewer maintenance;
• Representing the Cleveland – Cuyahoga County Port Authority in the litigation that compelled the US Army Corps of Engineers to maintain safe commercial navigation in Cleveland Harbor through timely dredging; and
• Defending a municipality in a class action alleging basement backup liability during an extreme wet weather event.

Lou is admitted to practice in the State of Ohio, the United States District Court, Southern District of Ohio, the United States District Court, Northern District of Ohio, and the United States Court of Appeals for the Sixth Circuit.

Lou received a BA in History, magna cum laude, from John Carroll University, where he was also the Outstanding History Scholar. He received his MA in History from Kent State University, and a JD, summa cum laude, from Cleveland Marshall College of Law.

• Cuyahoga County, Ohio Loaned Executive for water resources, 2013
• Served two terms as chair of the OSBA Environmental Law Committee from 2007 to 2009
• American Bar Association, Section on Environment, Energy and Resources
• City of Lakewood Planning Commission, 2015 to 2020

• 2024 Best Lawyers® “Lawyer of the Year” for Litigation – Environmental in the Cleveland area
• 2022 Notables in Law, Crain’s Cleveland Business
• Named by Chambers & Partners as a leading practitioner in Environmental Law in Ohio, 2004-2024
• Selected to the 2024 Ohio Super Lawyers list.
• Nationally recognized in “The Best Lawyers in America” for Environmental Law (since 2008), Environmental Litigation (since 2011) and Water Law (since 2013)
• 2021 Best Lawyers® “Lawyer of the Year” for Environmental in the Cleveland area
• 2018 Best Lawyers® “Lawyer of the Year” for Environmental in the Cleveland area
• 2017 Best Lawyers® “Lawyer of the Year” for Litigation – Environmental in the Cleveland area

A frequent speaker on water law and related topics, Lou’s annual “Water Law 101” presentation at the Ohio Stormwater Conference always draws a crowd. Presentation topics cover everything from nutrient regulation in Ohio, stormwater management, Integrated Planning and affordability, to the potential impact of emerging regulations and ethical requirements for lawyers and engineers. Lou speaks in a variety of forums, including multiple NACWA seminars, One Water, the Northeast Ohio Law Directors Association, Ohio Transportation Engineering Conference, and the Ohio State Bar Association’s Environment, Energy and Resources Law Seminar.

Presentation highlights include:

• “Post-Sackett Wetlands: The Regulated Perspective,” Ohio Stormwater Conference, May 9, 2024
• “Sources, Fate, and Transport of Nutrient Regulation,” Ohio Stormwater Conference, May 9, 2024
• “Water Law 101” and “Water Law 102,” Ohio Stormwater Conference, May 9, 2024
• “Environmental Policy in 2024 and Beyond,” EnviroScience Client Seminar, February 21, 2024
• “Perspective: CSOs Post Long-Term Control Plans,” Strand CSO Workshop, January 24, 2024
• “Wet Weather Permitting: You Did It! You’re Finally Reaching the End of Your Long-Term Control Plan. Now What?,” NACWA Legal Conference, November 9, 2023
• “Water Rights and Water Law 101,” CWRU Engineering, October 26, 2023
• “A Changing Landscape: How the Hot Topics in Environmental Law are Shaping Ohio’s Future,” Ohio Transportation Engineering Conference, October 18, 2023
• “Regulatory Update: How the Hot Topics in Environmental Law are Shaping Stormwater,” Ohio Stormwater Association, October 5, 2023
• “Communicating with the Public on Wet Weather Consent Decrees and other water infrastructure programs,” Ohio Stormwater Conference, May 11, 2023
• “Nutrients: Important issues coming to a Great Lake near you,” Ohio Stormwater Conference, May 11, 2023
• “Water Law 101” and “Water Law 102,” Ohio Stormwater Conference, May 11, 2023
• Parma Water Summit, March 25, 2023
• “Leveraging Water Assets and Delivery of Efficient Government Services,” Cuyahoga County Planning Commission Staff March 20, 2023
• “The Strong-Arm of the Law: From Narrative to Numeric in Euclid’s Ohio’s NPDES Permit,” NACWA National Clean Water Law and Enforcement Seminar, November 17, 2022
• “Engineering Ethics: a Lawyer’s Perspective,” NESOWEA Supervisors & Ethics Seminar, November 3, 2022
• “Water Rights and Water Law 101,” CWRU Engineering, November 1, 2022
• “Water Law: Headlines and Hot Topics,” OTEC, October 25, 2022
• “Ohio Water Law 101,” OTEC, October 25, 2022
• “NE Ohio Stormwater Overview and Update,” NEOLDA, October 20, 2022
• “Regulatory Update & Emerging Stormwater Issues,’” Ohio Stormwater Association, October 5, 2022
• “Engineering Ethics: a Lawyer’s Perspective,” One Water, July 28, 2022
• “Euclid’s NPDES Permit and New Frontiers in Nutrient Regulation,” One Water, July 28, 2022
• “The Municipal Toolbox: Tools and Legal Strategies for Stormwater Management,” Ohio Stormwater Conference, May 13, 2022
• “Nutrients, Nutrients, Nutrients!” Ohio Stormwater Conference, May 13, 2022
• “Ohio Water Law 102,” Ohio Stormwater Conference, May 13, 2022
• “Ohio Water Law 101,” Ohio Stormwater Conference, May 13, 2022
• “Integrated Wet Weather Improvement Plan for Lakewood, Ohio,” April 20, 2022
• “Nutrients and New Frontiers in Clean Water Act Regulation,”
• 37th Annual Ohio Environment, Energy and Resources Law Seminar, April 1, 2022
• Parma Water Summit, March 24, 2022
• “Ohio Water Law 101,” Ohio Federation of Soil and Water Conservation Districts Annual Partnership Meeting, February 28, 2022
• “Ohio Water Law 102,” Ohio Federation of Soil and Water Conservation Districts Annual Partnership Meeting, February 28, 2022
• “Ohio Water Law 102: Basic Legal Issues,” 2021 Stormwater Conference, May 20, 2021
• “Ohio Water Law 101,” 2021 Ohio Stormwater Conference, May 20, 2021
• “Ohio Water Law 101,” 2020 Ohio Stormwater Conference, August 27, 2020
• “2019 Infrastructure Funding: How to get it and spend it wisely,” Toledo, September 10, 2019
• “2019 Infrastructure Funding: How to get it and spend it wisely,” Cincinnati, June 25, 2019
• “Ohio Water Law 101,” 2019 Ohio Stormwater Conference, May 9, 2019
• “Funding Stormwater Solutions: Legal and Practical Considerations,” 2019 Ohio Stormwater Conference, May 9, 2019
• “Who Owns Which Ditch: The Basics of Ohio Ditch Law,” 2019 Ohio Stormwater Conference, May 9, 2019
• “2019 Infrastructure Funding: How to get it and spend it wisely,” Cleveland, May 7, 2019
• “2019 Infrastructure Funding: How to get it and spend it wisely,” Canton, April 30, 2019
• “Integrated Wet Weather Improvement Plan for Lakewood, Ohio,” Wet Weather Partneship, April 25, 2019
• “Water Law 101,” Tinker’s Creek Watershed Partners Ethics & Engineering Professional Development Workshop, September 14, 2018
• “Adaptive Management in Ohio,” Wet Weather Partnership, May 17, 2018
• “Clean Water Act: New Developments and Opportunities,” Indiana MS4 Partnership, May 15, 2018
• “Ohio Water Law,” 2018 Ohio Stormwater Conference, May 10, 2018
• “Legal Roundtable,” 2018 Ohio Stormwater Conference, May 10, 2018
• “Toxic Blobs and Ohio Jobs: Ohio v. USACE and the Future of Lake Erie Dredge Management,” 33rd Annual OSBA Environment, Energy and Resources Law Seminar, April 13, 2018
• “Drinking Water: Public Health Priority,” Moderator, 33rd Annual OSBA Environment, Energy and Resources Law Seminar, April 12, 2018
• “Green Infrastructure and Integrated Planning,” CMBA Environmental Law Institute, December 8, 2017
• “Foundations of Water Law,” Cleveland Division of Water, December 5, 2017
• “Admin Law in its Golden Age-Why Its Currently All the Rage,” NACWA National Clean Water Law Seminar, November 15, 2017
• “Management of Green Infrastructure on Private Property,” with Kevin Campanella of Burgess & Niple, Stormwater Solutions Conference, November 9, 2017
• “Clean Water Act,” Stormwater Solutions Conference, November 9, 2017
• “The Safe Drinking Water Act and Current Trends and Developments in Water Law,” Greater Cincinnati Water Works, November 1, 2017
• “Current Trends and Developments in Water Law,” Cleveland Division of Water, October 31, 2017
• “Ohio Water Law and Clean Water Act 101,” Greater Cincinnati Water Works, October 25, 2017
• “The Safe Drinking Water Act,” Cleveland Division of Water, October 24, 2017
• “Clean Water Act 101,” Cleveland Division of Water, October 17, 2017
• “Ohio Water Law,” Cleveland Division of Water, October 10, 2017
• “Ohio Water Law and Current Trends,” Dayton Society of Professional Engineers, July 13, 2017
• “Changing Water Law: A Local Government Survival Guide,” Northeast Ohio Law Directors Association, June 8, 2017
• “Ohio Water Law: A Primer,” Ohio Stormwater Conference, May 11, 2017

Lou is also a co-author, with Keely J. O’Bryan, of “Innovative Local Development Leverages EPA’s New Integrated Planning Framework,” published in the Cleveland Metropolitan Bar Journal in October 2015.