Lake Michigan Seawall Permits: A State-by-State Guide for 2026

Published July 28, 2026 by Lake Michigan Seawalls

The first question a lakefront owner asks about a seawall is what it costs. The question that should come first is whether you can legally build it, and on what terms. Shoreline protection on Lake Michigan is one of the most heavily regulated things you can do on your own property, because part of the work happens on land the public owns. Getting the permitting wrong does not just risk a fine. It can mean tearing out a wall you already paid to build. This guide walks the framework state by state so you know what you are dealing with before the first dollar is spent.

The One Line That Decides Everything: the OHWM

Every permit question on the Great Lakes starts with a single elevation: the ordinary high water mark, or OHWM. It is the legal boundary between your private upland and the state-owned bottomlands of the lake. On Lake Michigan, Michigan defines the OHWM at 580.5 feet on the International Great Lakes Datum of 1985. Work landward and above that line is generally your own business. Work lakeward and below it is on public bottomlands, and that is what pulls in state and federal review. A seawall, by its nature, is built right at that boundary, which is why almost every wall project crosses the line and needs a permit.

One note for the years ahead: the International Great Lakes Datum itself is scheduled to be updated in 2027, and that will change the reference elevation used for the OHWM. The concept will not change, but the exact number will, so confirm the current figure with the agency when you apply. The full detail on Michigan's OHWM is on the EGLE submerged lands page. Where your wall sits relative to this line is also tied to the lake's level in a given year, which we cover in our guide to Lake Michigan water levels and erosion risk.

Two Permits, Not One: State and Federal

Here is the part that surprises people. On Lake Michigan you are usually dealing with two separate authorities, not one. The state regulates its own bottomlands, and the federal government, through the US Army Corps of Engineers, regulates work in navigable waters of the United States. A single seawall can need sign-off from both.

The federal side runs on two well-known authorities. Section 10 of the Rivers and Harbors Act covers structures and work in navigable waters, which is what a seawall in the lake is. Section 404 of the Clean Water Act covers the discharge of fill material, which comes into play when a project places stone or backfill below the water line. The states have built their programs to coordinate with the Corps, and in Michigan the two reviews are often submitted together on a joint permit application. That coordination is a convenience, not a shortcut: both authorities still have to approve the work.

Michigan: EGLE and Part 325

In Michigan, shoreline structures below the OHWM are permitted by the Department of Environment, Great Lakes, and Energy, EGLE, through its Water Resources Division. The governing law is Part 325 of the Natural Resources and Environmental Protection Act, the Great Lakes Submerged Lands Act. A seawall or revetment on the bottomlands is exactly the kind of activity Part 325 was written to review. EGLE has no Part 325 jurisdiction above and landward of the OHWM, which is why that elevation matters so much: it decides whether you are inside the program or outside it.

The Michigan process is generally a joint application that routes to both EGLE and the Detroit District of the Army Corps of Engineers. Depending on the scope, the work may qualify for a minor or general permit category, which moves faster, or it may need a full individual review with public notice. What tips a project from one lane to the other is usually its size, whether it changes the existing footprint, and its potential effect on adjacent shoreline and lakebed.

Indiana, Illinois, and Wisconsin

The other three shoreline states run their own programs, each with its own agency and framework, all coordinating with the Army Corps on the federal side.

• Indiana. The Indiana Department of Natural Resources regulates construction along the Lake Michigan shoreline and on the lakebed. Indiana has a relatively short but intensely developed stretch of coast, and its DNR reviews shoreline structures for their effect on the beach and neighboring properties.
• Illinois. Illinois exercises regulatory authority over Lake Michigan through the Department of Natural Resources, Office of Water Resources. The Illinois shoreline is heavily engineered, and OWR reviews new and modified structures along it.
• Wisconsin. The Wisconsin Department of Natural Resources permits structures on Great Lakes bottomlands under Chapter 30 of the Wisconsin Statutes, the state's long-standing framework for work on navigable waters.

The details, thresholds, and application forms differ in each state, and they change, so treat this as the map, not the turn-by-turn directions. The right move on any specific parcel is to confirm the current requirements directly with the state agency and the Army Corps before you design the wall, because the permit constraints often shape the design itself, including the material and structure type that will be approved for your site.

Repair Versus New Construction

Not all projects carry the same permitting weight. Rebuilding a legally permitted wall in kind, meaning the same footprint and materials, can sometimes qualify for a faster minor or general permit, because the agencies are not evaluating a brand-new impact. Building a new wall where none existed, extending a wall lakeward, or changing its type is a larger review. This is one more reason the repair-versus-replacement decision is not only about engineering and cost; it also changes what you have to get approved. Even so, do not assume a repair is exempt. Unpermitted work below the OHWM carries the same enforcement risk whether it is new or a rebuild, so confirm first.

What the Application Needs, and When to Start

A complete application generally includes a site plan, drawings and cross-sections of the proposed wall, its location relative to the OHWM, and a description of methods and materials. The agencies want to understand the effect on the lakebed, on drainage, and on the neighboring shoreline, since a wall that fixes one property can accelerate erosion next door. A design prepared by someone who builds to these standards moves through review with fewer rounds of questions.

Timing is the practical trap. Permit review runs from a few weeks for a straightforward minor permit to several months for a full individual review, and high-water years flood the agencies with applications and stretch the queue. If you want to build in a given season, start the permitting the season before. The lake does not wait for paperwork, and the findings from your own annual seawall inspection are exactly the evidence that should trigger an early application rather than a scramble after the next storm.

Why Owner-Run Permitting Goes Sideways

The most common permitting mistakes we see are not exotic. An owner assumes a repair is exempt and skips the application. A wall gets designed without regard to the OHWM and then cannot be permitted as drawn. A project ignores the flanking effect on a neighbor and draws an objection that stalls the review. Or someone builds first and applies later, which is the worst position to negotiate from. None of these are hard to avoid with the right sequence: establish where the OHWM falls on your parcel, design a wall that the state and the Corps will approve, submit early, and build only once the permits are in hand. That order protects the investment. The reverse order risks it.

The Bottom Line

A Lake Michigan seawall is a regulated structure, not a landscaping project, because part of it stands on public bottomlands below the ordinary high water mark. That means a state permit in every case, through EGLE in Michigan or the DNR in Indiana, Illinois, or Wisconsin, and usually a federal permit from the Army Corps of Engineers alongside it. Repairs can move faster than new builds, timelines run from weeks to months, and building without the permit is the one path that can force you to tear the wall back out. Sort the permitting first, and the rest of the project rests on solid legal ground. We handle permit-ready scopes across all four states as a matter of routine, which is the least glamorous and most protective part of the work.

Frequently Asked Questions

Do I need a permit to build a seawall on Lake Michigan?

Almost always, yes. Any seawall or revetment work below the ordinary high water mark sits on Great Lakes bottomlands and needs a state permit, and usually a federal one from the Army Corps of Engineers too. All four shoreline states, Michigan, Indiana, Illinois, and Wisconsin, regulate this work. Building without the permit risks fines and an order to remove the wall.

What is the ordinary high water mark and why does it matter?

The ordinary high water mark, or OHWM, is the legal elevation that separates private upland from state-owned Great Lakes bottomlands. On Lake Michigan, Michigan sets it at 580.5 feet IGLD85. Work below that line is on public bottomlands and triggers state and federal permits. It is the single line that decides whether your project needs review at all.

Who regulates Lake Michigan seawalls in Michigan?

In Michigan, the Department of Environment, Great Lakes, and Energy, EGLE, permits shoreline structures below the OHWM under Part 325, the Great Lakes Submerged Lands Act. The US Army Corps of Engineers regulates the same work federally. The two reviews often run together through a joint permit application, but both authorities have to be satisfied before construction.

Do I need a permit to repair an existing seawall?

Often yes, though repair of a legally permitted wall in kind can sometimes move through a faster minor or general permit than new construction. It depends on the state, the scope, and whether you are changing the footprint or materials. The safest step is to confirm with the state agency before starting, because unpermitted repair below the OHWM carries the same risk as unpermitted new work.

How long does a Lake Michigan seawall permit take?

It varies widely by state, scope, and season, from a few weeks for a minor or general permit to several months for a full individual review with agency coordination. High-water years bring a surge of applications that lengthens the queue. Apply early, well before the construction season you are targeting, and expect a longer timeline for new walls than for in-kind repairs.

What happens if I build a seawall without a permit?

Unpermitted work on Great Lakes bottomlands can draw enforcement, fines, and an order to modify or fully remove the structure at your own cost, on top of having to apply for the permit after the fact with no guarantee of approval. It can also cloud a future property sale. The permit is far cheaper than the enforcement, so it is not a corner worth cutting.