Illinois Waters and Wetlands

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Learn everything you need to know about Illinois waters and wetlands. 

Why are Waters Defined Differently by State?

In the U.S., the Clean Water Act (CWA) protects waters. Jurisdictional Waters of the United States (WOTUS) are given extensive protection under this act. However, this act provides vague definitions for these waters, leading to the ambiguity of interpretations of these waters. States have added additional definitions to waters to gain clarity and protect waters that do not fall under the CWA jurisdiction as interpreted by different administrations.

Additionally, water use and needs vary by state—the different biogeographic regions in each state impact primary water sources and regulations are regionally specific. Protected waters serve as a wildlife habitat for many protected fish, plants, and other species that vary significantly by state. This variety of life and water use creates the need for state-specific regulations.

Who Regulates Illinois Waters?


Illinois Environmental Protection Agency

The Illinois Environmental Protection Agency protects the state's natural resources and enforces the state's environmental laws regarding water quality, air quality, conservation, and other state standards. This agency has subsections for ecosystem restoration services, land and recreation, and regulatory programs. This statewide office ensures developers uphold state and federal standards.

Illinois Department of Natural Resources

This resource protects the state's cultural, recreational, and natural resources. The Interagency Wetlands Policy Act of 1989 provides many of this department's waters and wetlands regulatory powers.

Illinois Administrative Code

The Illinois Administrative Code contains all the statewide rules and regulations. Within the code are all the state's water regulations. These regulations are specific to the state and may enforce a federal ruling.

Illinois Groundwater Regulations

Illinois's Groundwater Protection Program expands upon the federal Safe Drinking Water Act to maintain groundwater quality. This rule includes restricting waste discharge into groundwater systems and ensuring that groundwater use is for a legitimate cause. This rule is under the authority of the Illinois Environmental protection Agency. This rule includes:

  • Maximum setback zone: up to 1000ft surrounding county and municipal wells 

  • Groundwater Advisory Council (GC): appointed officials to review policy relating to groundwater

  • Wellhead protection: When developing new community water supply wells, protections for the processes of the gathering of driller's logs and safe yield information has extended 

  • Ambient Monitoring: analyzes and establishes a baseline and overview for major aquifers' water quality and quantity in Illinois. Monitors effects the Clean and Safe Drinking Water Acts have on Illinois groundwater protection.

  • Surveys and Mapping Assessments: The Illinois EPA conducts surveys of wells, including checking the radius of the well's setback zone and determining the route of possible contamination sources

  • Groundwater Protection Planning Routes: identifies, monitors, and implements programs for additional groundwater protection needs

Illinois Water Quality Standards

The Environmental Protection Agency (EPA), a federal agency, sets the Surface Water Quality Standards that the states uphold. These standards guide the regulations for surface waters, such as lakes, wetlands, streams, rivers, and other waterways. Surface water quality is detrimental to the health of the environment and individuals. Therefore, extensive regulations and multi-level agencies work to protect these waters.

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The Great Lakes Compact


What is the Great Lakes Compact?

The eight Great Lakes states, the United States Congress, and President Bush approved this compact in 2008. This compact between Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin exists to safeguard the largest freshwater ecosystem in the world. Additionally, this rule is a binational agreement with Canadian provinces Quebec and Ontario.

This compact bans diverting waters from the Great Lakes Basin unless there is a necessary cause. This rule also requires states to establish a state-specific regulatory program to aid basin management. 

Great Lakes Protection

The Great Lakes contain 90% of North American surface water and 20% of all the fresh surface water in the world. Therefore, the water quality and quantity of these lakes are heavily protected. 

The surface water quality standards in each state and additional Great Lakes protections aid in preserving and restoring these waters. In addition, the Great Lakes Fund exists to fund research on these waters. Additional funds are provided to Great Lakes states for green energy projects to preserve these waters. A proposed rule, The Great Lakes Water Protection Act, would amend the Federal Water Pollution Control Act to include banning the redirection of waste streams into the Great Lakes by public wastewater treatment facilities. 

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Illinois Wetlands


Illinois Wetlands Definition

Illinois adopted the 1978 federal wetlands definition of a wetland. This definition defines a wetland as a region of predominantly hydric soils. That surface or groundwater saturates at a frequency and duration sufficient to support, under typical circumstances, an abundance of hydrophytic vegetation adapted for life in saturated soil conditions. 

History and Importance of Illinois Wetlands

Illinois wetlands provide a wildlife habitat for various non-endangered and endangered species. These wetlands connect to significant rivers in the state and impact downstream waters. Decades of clearing land for agriculture and redirection of the Cache River, the primary flow source for wetlands, into the Ohio River has put these waters at risk.

Protection for Illinois Wetlands: Interagency Wetlands Policy Act of 1989

This act gives the Illinois Department of Natural Resources (IDNR) regulatory power for state-funded projects that will impact wetlands. The act establishes definitions and processes for delineating wetlands and criteria for regulation and jurisdiction. 

Illinois Wetlands Conservation Strategy (IWCS)

This rule is a proposed plan for Illinois wetlands conservation and restoration. The plan outlines the steps for implementing wetlands programs and wetlands protections initiatives. The Interagency Wetlands Committee, created by the Interagency Wetlands Policy Act of 1989, oversees this initiative act. Further wetlands regulations are likely to follow this act.

Cache River Wetlands Protections

The Cache River Wetlands make up 91% of the swamp and wetland communities in the state. This biodiverse wetland habitat supports some of the oldest living things east of the Mississippi river, including -1000-year-old cypress trees. They are seen as internationally essential and ranked equivalent to the Florida Everglades.

The Cache River Joint Venture Program, a partnership between Ducks Unlimited, the United States Fish and Wildlife Services, the Nature Conservatory, and the Illinois Department of Natural Resources, protects a large region of these wetlands. It establishes much of the area as a conservation area. Activities around and on these waters impacting life and water quality are subject to standards set by Illinois in conjunction with these other agencies.

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Illinois Rivers


Illinois Rivers, Lakes, and Streams Act

This act gives the Illinois Department of Natural Resources jurisdiction over these waterways. The department will monitor water quality and quantity for these waterways and regulate the actions that impact them. This act supports standards set by the Federal Water Pollution Control Act (1948), also known as the Clean Water Act, and other state regulations for water quality.

Mississippi River Protections

The Mississippi River water quality impacts multiple states. This river is crucial to these communities and is a wildlife habitat for many endangered species. The main danger to this river in Illinois is nutrient loading. Multiple state regulations have been set to limit excess phosphorus and nitrogen in the Mississippi and protect water quality. An important rule is the Illinois Partners for Nutrient Loss Reduction Act. This act provides the fund to support these environmental efforts.

How Can Protected Illinois Water Impact Land Developers?

Protected waters fall under many federal, state, and local regulations. These waters can be challenging to identify, as in the case of temporary waters, and have consequences later in development. Delaying or incorrectly identifying waters can result in project delays and expensive recovery efforts.

Additionally, Illinois water serves as a habitat for many protected species, such as fish and vegetation. Due to this, developments will be subject to other federal and state regulations, such as the Endangered Species Act. Additionally, more restrictive rules may apply for individual wetlands, resulting in project failure. Proper environmental due diligence aids in the identification of these waters and navigations of regulations.

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How to Identify Protected Waters on Your Project Site


Environmental Consultants

Environmental consultants are trained to survey sites for potential environmental impacts. These consultants know the state, federal, and their respective region's regulations. The consultant can recommend necessary permits and steps to ensure environmental compliance if they find an environmental risk-such as protected water. This traditional process is completed manually by an environmental consultant over weeks or months. 

National Hydrography Dataset

This data depicts the nation's water drainage network. Software platforms use this data, which is available for download by the public. As the USFWS source, this tool does not outline permits needed, the jurisdiction of waters, and other regulations. Though these due diligence tools are helpful, one of the easiest ways to identify wetlands is to use environmental due diligence software like Transect.

Environmental Permitting Software

Transect uses machine learning and integrated datasets, such as the National Hydrography Dataset, to automate the mapping of WOTUS. This software uses prior and current data about water locations to assess a specified region. The software provides the area and likelihood of regulated water appearing on a site in the jurisdiction of the water and includes a corresponding confidence level in its occurrence. Additionally, Transect will also provide a site-specific list of permits and next steps required to comply with federal, state, and local laws. This mapping tool can aid in selecting the right site for a project by generating this report in minutes.

Transect Software helps land developers discover these waters on any given parcel of land.

Free Permitting Checklist

Practical Tips to Avoid Environmental Risk on all Your Projects

Download our environmental permitting checklist to get a step-by-step list of ways to protect your project from the 9 most common environmental risks.

Download Your Checklist