Wetland delineation Illinois cost with Lake, DuPage and Cook County review fees

A wetland delineation in Illinois costs about $2,500 to $4,500 on a parcel under two acres, $4,000 to $6,000 at five acres and $6,000 to $14,000 at 10 to 20 acres, plus $1,200 to $4,000 for a licensed land surveyor to locate the flags on your plan. In the Chicago area you then pay a county review fee on top: $250 to $2,500 at the MWRD in Cook County, $610 to $1,585 in DuPage County and $480 and up in Lake County. Those local reviews are the reason an Illinois delineation is still needed when the Army Corps of Engineers says a wetland is not its problem.

Illinois has no state permit program for wetlands on private land. The Interagency Wetland Policy Act of 1989 governs projects that state agencies fund or carry out, not your subdivision or your house. That leaves two layers: the Corps, whose reach shrank after the Supreme Court decided Sackett v. EPA in 2023, and the countywide stormwater ordinances in the collar counties, which never depended on federal jurisdiction in the first place.

How much does a wetland delineation cost in Illinois?

The consultant's price follows acreage, access and how much of the site sits in the transition zone where soil pits and plant plots have to be recorded closely. What changes in northeastern Illinois is the list of local fees and who is allowed to sign the work.

The consultant ranges are 2026 market ranges, not quotes. The government fees come from each agency's published schedule: the MWRD figures are Section III of Appendix F to its Watershed Management Ordinance, which also says single-family home developments are exempt from fees except for projects involving wetlands or riparian areas. So the house that would otherwise have paid nothing does pay once a wetland is on the lot. Confirm the DuPage and Lake County figures with the office before you budget, since both counties adjust their schedules.

Do I still need a wetland delineation in Illinois after Sackett?

In the collar counties, usually yes. Sackett limited federal jurisdiction to wetlands with a continuous surface connection to a regulated water, so plenty of Illinois wetlands, the wet swale behind a cul-de-sac or a farmed depression on the edge of a field, are no longer federal. Lake County calls them Isolated Waters of Lake County and regulates them through its Watershed Development Ordinance. Cook County, through the MWRD, regulates isolated wetlands and riparian areas the same way. DuPage County requires a stormwater certification for any development within 100 feet of a wetland, on the site or off it, whatever the Corps thinks.

The practical point is that a "no federal jurisdiction" answer from the Corps does not clear your permit. In Lake County, the Stormwater Management Commission told enforcement officers in October 2024 that when impacts are proposed, the developer needs an onsite delineation by or under the supervision of a Lake County Certified Wetland Specialist, and in most cases a written jurisdictional determination from either the Corps or the SMC. Only those two can issue one in Lake County. The SMC quotes two to three weeks for its preliminary determination; the Corps' turnaround is, in the SMC's own word, indeterminate.

Who can do a wetland delineation in Illinois?

Illinois does not license wetland delineators, but the counties decide whose report they accept. Lake County keeps a list of Certified Wetland Specialists. DuPage County requires the determination to come from a qualified environmental scientist, and county staff do not delineate private property, so you hire a consulting firm. The MWRD accepts a wetland specialist who holds either of those county credentials or the Society of Wetland Scientists' Professional Wetland Scientist certification, or who has a degree in a biological or earth science plus three years of full-time wetland work in the Upper Midwest or at least 100 delineations there.

Ask any consultant you are pricing which of those credentials they hold, and whether their report has cleared review in your county recently. A report written to the wrong county's checklist is the most common way an Illinois delineation gets paid for twice.

Why the surveyor is part of the price

The consultant flags the line in the field; the county wants it on your plans. Lake County's guidance is explicit that when disturbance is within 100 feet of a wetland, the surveyed boundaries go on the site development plans, and the buffer is measured from that line. DuPage sets buffers at 50 feet around most wetlands and 100 feet around critical ones. On a half-acre lot, a buffer drawn from a flag line that is off by eight feet can decide whether the garage fits.

So the survey is not a formality. A licensed land surveyor locates each numbered flag, draws the wetland and the buffer, and ties both to your deed lines, setbacks and proposed building. Book the survey while the ribbons are still up, give every bidding firm the consultant's flag count, and ask for the line on the same coordinate base as the engineer's grading plan. On a larger tract, an orthomosaic from a drone flight over the parcel gives the consultant a current base map for planning transects, but it does not replace the ground survey the county reviews.

A worked example with a half-acre lot in a Lake County village

A builder buys a half-acre infill lot in a Lake County village to put up one house. The rear of the lot drops into a wet swale that drains to a ditch, not a stream, and the house pad would sit about 60 feet from it. Because disturbance is within 100 feet, a delineation is required.

• Delineation and report by a Lake County Certified Wetland Specialist: about $2,500 to $3,500, done in two weeks in the growing season.
• Surveyed wetland boundary and buffer on the site plan: $1,200 to $2,000.
• SMC isolated wetland boundary verification: $480 for the one wetland.
• If the house and grading stay outside the buffer: a Letter of No Impact request, which the SMC says it usually issues in two to three weeks.

Total to a buildable answer: roughly $4,200 to $6,000 and five to seven weeks. Skip it, and the village's enforcement officer holds the watershed development permit, which holds the building permit.

Common questions

How much does a wetland delineation cost in Illinois?

Most small lots cost $2,500 to $4,500 for the delineation and report, five acres $4,000 to $6,000, and 10 to 20 acres $6,000 to $14,000. Add $1,200 to $4,000 for the survey of the boundary and, in the collar counties, a county review fee from $250 at the MWRD to $1,585 for a large DuPage development.

Does Illinois regulate isolated wetlands?

Not statewide for private land. The Interagency Wetland Policy Act covers state agency projects only. But Lake County, DuPage County and the MWRD in Cook County regulate isolated wetlands through their stormwater and watershed ordinances, so a wetland the Corps does not regulate can still need review, a buffer and sometimes mitigation.

How big is a wetland buffer in DuPage County?

Fifty feet around most wetlands and 100 feet around wetlands the county classes as critical. The buffer is measured from the delineated edge, so the accuracy of the surveyed line matters as much as the delineation itself.

Where this fits in your project

An Illinois wetland answer is two jobs: a consultant who flags the line and a surveyor who puts it on your plan. For the national price picture see our wetland delineation cost guide, compare the state-run system next door in wetland delineation in Wisconsin, and if you need the whole job scoped, start with wetland delineation services. When you are ready to price the survey, post the parcel once and up to 3 licensed Illinois land surveyors covering your county will send written quotes, usually within 24 hours.