Dennis G. Walsh



Dennis Walsh has over 34 years of experience in representing public bodies including counties, municipalities, local libraries and library districts, park districts, school districts, fire protection districts, townships, Metra and intergovernmental cooperative agencies in all areas of practice. He is currently the Village Attorney for the Village of Orland Park.

He has extensive experience in resolving the complexities and statutory requirements associated with budgets, tax levies, bidding and procurement, the acquisition and sale of real estate, environmental and construction matters, open meeting and freedom of information laws, policy review and revisions, employment issues, contracts and intergovernmental agreements. He assists public officials and employees with understanding their roles and duties including their ethical requirements. Dennis has been involved in defending complex civil rights, public official, police and constitutional claims (involving both monetary and injunctive relief), as well as lawsuits involving personal injury, defamation, wrongful death, breach of contract and virtually all areas of municipal law, including zoning and land use.

Dennis also oversees the firm’s environmental practice. He has been providing expert assistance in environmental law to the firm’s private and public sector clients and other attorneys since he joined the firm in 1986, and he has experience under the full range of state and federal clean air, water, noise and hazardous substance statutes and regulations including CERCLA, RCRA, LUST and the Illinois Site Remediation Program. He assists the firm’s clients in responding to sites containing hazardous substances and waste including contaminated quarries, public utilities, gas stations, former manufactured gas plants (MGP), incinerators, abandoned landfills and abandoned, idled, or underused industrial and commercial properties where expansion or redevelopment has been hindered by real or perceived contamination. He was lead counsel in one of this nation’s largest remediation projects of an MGP site. 

Dennis has been involved in complex environmental and toxic tort litigation, including compliance and enforcement actions under the federal and state regulations. He represents both private and public purchasers and sellers of properties in due diligence ranging from individual buildings through corporate-wide asset acquisitions, in crafting the appropriate instruments to effect the transfer of environmental liabilities as intended by the parties to the transaction, and has supervised all levels of environmental assessments (Phases I, II and III). He counsels the firm’s clients on environmental regulations and variances, highway authority agreements, groundwater ordinances, deed restrictions and other institutional controls under the Illinois Tiered Approach to Cleanup Objectives (TACO) and eminent domain issues involving contaminated properties. He has been involved in corporate acquisitions, real estate transactions, and storage tank and hazardous waste remediation planning and oversight. He is experienced with negotiating environmental insurance coverage, and he has worked with policy holders in determining the obligations to defend and indemnify with respect to environmental matters. He assists clients through the maze of local siting requirements and community host agreements for new pollution control facilities, including landfills and transfer stations. He assists municipal clients in obtaining grants under the Illinois Brownsfields Redevelopment Grant Program

In addition to his local governmental practice, he maintains an extensive private sector practice and advises a number of individual and corporate clients on their legal needs.

Dennis graduated magna cum laude from the State University of New York Polytechnic Institute receiving a B.P.S. degree in 1982.

He received his J.D. degree from the UIC John Marshall Law School in 1986. While attending UIC John Marshall, Dennis served as a member of the Moot Court Executive Board and participated on the Irving P. Kaufman Securities Law National Competition Team. Dennis was also the executive editor of The Marshall Opinion, the school’s student newspaper.

Dennis is admitted to practice in the state of Illinois, the United States District Court for the Northern District of Illinois, the United States Court of Appeals for the Seventh Circuit and the Supreme Court of the United States.

Professional Affiliations

  • Dennis is a member of the Chicago Bar Association, the Illinois State Bar Association, the Illinois Government Lawyers Association and the International Municipal Lawyers Association.

Community Involvement

  • Dennis was President of the Orland Park Kiwanis Club and was actively involved in coaching youth sports.

Awards and Recognition

  • Dennis has been named a Leading Lawyer for many years, a peer-recommended distinction awarded to fewer than 5% of attorneys in Illinois.
  • Dennis has been profiled in the Leading Lawyers Magazine – Real Estate, Construction & Environmental Edition for 2018.


  • Common Environmental-Related Requests Made to Municipalities – Illinois Local Governmental Lawyers Association, Mar/Apr 2024 
  • What You Don’t Know About Your Underground Storage Tanks Can Hurt You – Illinois Municipal Review
  • Installation and Operation of Underground Storage Tanks – Illinois Municipal Review
  • Responding to a Release from Your Municipal Underground Storage Tank – Illinois Municipal Review
  • Out of Service Underground Storage Tanks and Closure Procedures – Illinois Municipal Review
  • Bringing Your Underground Storage Tank Up to Date – Illinois Municipal Review
  • Reimbursement to Local Governments for Emergency Responses to Hazardous Substance Releases – Illinois Municipal Review
  • Municipal Liability Under Superfund – Illinois Municipal Review and Vol 21 No.3
  • Current Municipal Problems – Clark Boardman Callaghan
  • Protecting Your District from Environmental Liability Associated with Land Acquisitions – KTJ Education Law Report
  • Corporate Successor Liability Under CERCLA – 79 Ill. B.J. 425 and Westlaw Journals & Law Reviews Database
  • Library Law: Is the Site for Your Library Really Clean? – North Suburban Library System
  • The Open Meetings Act – author, Township Officials of Illinois Town Clerk’s Handbook
  • The Sunshine Laws: Open Meetings & Freedom of Information Acts – co-author, IML
  • Manual on Conflict of Interest and Liability of Illinois Elected Officials – co-author, IML
  • Manual on Police and Fire Disciplinary Matters – co-author, IML
  • Manual on Liquor Licensing and Regulation – co-author, IML
  • New Laws for Local Libraries – Linkedin
  • The Need to Act Fast for Temporary Relief From the New Chloride Water Quality Standards – Linkedin
  • Municipal Authority to Investigate and Remediate Abandoned and Unsafe Contaminated Property – Linkedin


  • Dennis has spoken to various groups on a wide range of legal topics.

Representative Matters

  • Brownfields Redevelopment

Dennis has successfully led negotiations and litigation for several public and private sector clients in high profile environmental cleanups and enforcement actions. He is and has been actively involved in large and complex Brownfields redevelopment and remediation projects for a vary of clients including:

    • Barrie Park, Oak Park – Dennis was lead counsel in one of the largest investigations and remediation projects of a manufactured gas plant in the United States. The cleanup started with the park and proceeded to two surrounding residential areas, with over 60 properties undergoing investigation, cleanup and restoration and the remediation of over 400,000 tons of coal tar residuals and soil.
    • River Edge Park, Aurora – Dennis provides legal support to several of the firm’s clients related to the investigation and cleanup of several former MGP sites in Illinois. One former MGP site is now the beautiful outdoor entertainment and recreation facility located on the banks of the Fox River in the City of Aurora.
    • Orland Park Downtown Main Street Triangle – Dennis assisted the Village of Orland Park in the complete redevelopment of its 27-acre Downton Main Street Triangle working on the varied and extensive environmental matters associated with the site that enabled University of Chicago Medicine to choose that location for the development of a 120,000 square foot medical facility.
    • Former State of Illinois Mental Health Facility, Tinley Park, IL – Dennis worked with the Village of Tinley Park to evaluate the environmental concerns and legal issues related to the purchase of a former State of Illinois mental institution. This 280-acre property had 49 former structures, associated steam tunnels, a power plant, water treatment facilities, a fueling facility and other operations including fill areas that were investigated for potential release of hazardous constituents and asbestos containing materials.
    • Redevelopment of former Holiday Inn Site, Oak Lawn – Dennis assisted the Village with environmental issues related to the agreement between the Village of Oak Lawn and Target Corporation for the redevelopment of the former Holiday Inn site. 
    • Development Site, River Forest, IL – Dennis represented the Village of River Forest in assessing the extent and cost of cleanup of a former dry cleaner as part of planned development in central River Forest.
    • Lake Street Redevelopment Area, Oak Park, IL – Dennis has assisted the Village of Oak Park in the redevelopment of properties formerly used as a coal-fired power plant, public works facility, former service stations, and a former bulk petroleum storage facility. The redevelopment activities were funded through Tax Incremental Funding initiatives and in one case were partially funded using Brownfields Tax Credits from the State of Illinois.
    • Lockformer, Lisle, IL – Dennis represented the Village of Lisle in a lawsuit against Honeywell International, Inc. and others seeking recovery of costs incurred by the Village to address the trichloroethylene (TCE) contamination on and from the Lockformer Company’s 711 Ogden Avenue site. 
    • Private Sector Clients – Dennis represents several private sector clients including a Fortune 500 oil company and commercial and residential real estate and other companies with respect to their varied environmental needs and litigation.
  • Class V: UIC Permit

Dennis worked on obtaining the first and only Class V Underground Injection Control (UIC) area permit from the Illinois Environmental Protection Agency (IEPA) ever issued in the State of Illinois to construct and eventually operate four (4) injection wells located within a fifty (50) acre parcel of land in the City of Aurora. This facility will dispose of non-hazardous lime sludge into a subterranean limestone and dolomite mine cavity which extends two hundred forty (240) to three hundred sixty-five (365) feet below the ground surface. Simultaneously while working with the IEPA to obtain this Class V permit, he negotiated a mining lease with one of the largest international mining companies in the world for the subsurface dolomite rights, and negotiated the sale of the surface of the property to a separate company for a new permitted CCDD (landfill) facility while also negotiating and settling (with no fine or penalty) with the IEPA all issues regarding alleged past environmental violations on the surface and transferred all past and future environmental liability to the new surface owners. At the same time, the City kept all mineral rights and other subsurface rights for royalty payments from the mining company.

  • Landfill and Transfer Station Siting Process

Dennis has been involved in waste facility siting decisions since 1998 and understands the legal, scientific and political hurdles that must be navigated to reach a sound siting decision. He has advised the County of Will, the Village of Maywood, the Village of Lombard, the City of Aurora, the City of West Chicago and the Village of Rockdale on the Illinois mandatory process for determining the appropriateness of solid waste facility locations. He has drafted ordinances and rules and regulations to implement the siting statute, including provisions for the applicants paying all the municipalities implementing costs. He has advised on and negotiated “Host Community Agreements” to obtain commitments and benefits which cannot be obtained in the siting process itself. He has trained clerks and other staff on how to implement the process and has served as hearing counsel for the host community. He has drafted the ultimate siting decisions including the development of conditions on the grant of siting approval, to ensure long term safe operations. He has successfully represented the host community on appeals to the Illinois Pollution Control Board and the Illinois Appellate Courts in any challenges to its decisions. Dennis represents Ogle County as special environmental counsel relating to the landfills located within the county and for its other environmental legal needs.

  • Rule Making: Chloride TLWQS

Dennis represents the Villages of Orland Park, Riverside, Romeoville, Tinley Park, Wilmette and the Cities of Oak Forest and Palos Heights as it relates to their petitions filed with the Illinois Pollution Control Board for a variance under Title IX of the Illinois Environmental Protection Act. These clients, like several other regulated parties, are requesting a variance from the deadline for complying with the new water quality chloride standards. In Docket 2008—009, the Board has been engaged in an extensive rulemaking process regarding designated uses, effluent limitations and water quality standards for the Chicago Area Waterways (CAWS). Sub docket D has involved the setting of water quality standards for the protection of aquatic life. The Board has adopted final aquatic life water quality standards for the CAWS and included in that rulemaking are new standards for chlorides. Subsequently, each petition for a variance from the chloride water quality standard became a petition for a time-limited water quality standard (TLWQS) which is a new mechanism for regulating relief. TLWQS are federally approvable water quality standard variances consistent with federal rules.