On the Madison lakes, the same deck can be fine on one lot and illegal two doors down, because each city and village measures the lakefront setback its own way. Madison averages the neighbors. Monona measures from an old meander line. Shorewood Hills uses a line drawn in 2002. Maple Bluff draws one for each lot. Here are the rules for each, then the state and county rules that apply on top.
Setback finder · Who regulates your shore · By municipality · Piers · Riprap and seawalls · Boathouses · Floodplain and lake levels
Who regulates your shore
Land within 1,000 ft of a lake is shoreland. Who writes the rules for it depends on whether the lot is in a city or village, or in a town: (Wis. Stat. 59.692)
- Cities and villages (Madison, Maple Bluff, Shorewood Hills, Middleton, Monona, McFarland) set their own lakefront setbacks in their zoning codes. State law only requires them to zone shoreland wetlands. (DNR)
- Towns (Westport on Mendota, Dunn on Waubesa and Kegonsa, Pleasant Springs on Kegonsa) are under Dane County's shoreland ordinance, Chapter 11. (Dane County Ch. 11)
- Land annexed into a city after May 7, 1982 carries a state minimum setback of 50 ft, and the county rules stay in force until the city adopts its own. Middleton applies 75 ft on that land. (Wis. Stat. 62.233)
- The DNR regulates anything at or below the water's edge everywhere: piers, riprap, seawalls, dredging and wetland fill.
Every municipality measures from the ordinary high-water mark (OHWM) except Monona, which uses its meander line. Most require a licensed surveyor to locate it on your plans.
By municipality
City of Madison Mendota, Monona, Wingra, Monona Bay
The setback follows the neighbors, and building on a lakefront lot often means a Plan Commission hearing.
| House or addition | The lakefront setback for a house is the average of the two neighboring houses (if within 20 ft of each other), the one developed neighbor's, or the median of the five nearest; 75 ft if none applies, and never closer than 25 ft. Any accessory building, and additions over 500 sq ft in 10 years, need a Plan Commission conditional use with a public hearing. Parts of the lot more than 300 ft from the water, or across a street, are exempt. |
|---|---|
| Deck | Uncovered decks no more than 3 ft above the ground may go in the lakefront setback. Higher decks may not. |
| Patio or terrace | Within 35 ft of the ordinary high-water mark, lot coverage is capped at 20%. |
| Boathouse | A boathouse is an accessory building, so it needs a conditional use on a lakefront lot, and it can't be built for living in. |
| Fence | Fences, walls and hedges are allowed in the lakefront setback. |
| Path or stairs to the water | Tree and shrub cutting is limited within 35 ft of the shoreline and no more than 30% of the frontage may be cleared. Retaining walls and bulkheads are allowed only to stop the shoreline from receding. |
| Setback | Neighbors' average, one neighbor's, or the median of five; 75 ft by default; never under 25 ft. |
| Hearing | Plan Commission conditional use for any accessory building or additions over 500 sq ft, with 30 days' notice to the alder and neighborhood first. |
| Survey | A registered surveyor's survey showing the high-water mark and the neighbors' setbacks. |
Read the code · City of Madison Zoning, 608-266-4551 · Remodeling in Madison
Village of Maple Bluff Mendota
Each lot's lake setback is a line drawn on the village zoning map, and everything hard-surfaced has to stay behind it.
| House or addition | The Lake Mendota setback isn't a fixed number: it's the line drawn for your lot on the village zoning map. Exterior work also needs village design review. |
|---|---|
| Deck | Decks, patios and other hard surfaces must meet the same lake setback as the house. In a required setback, no deck or terrace may be more than 2 ft above grade. |
| Patio or terrace | Patios and walks must meet the same lake setback as the house. One open-sided structure up to 200 sq ft, at least 35 ft from the water, can be approved by the Building Board if it doesn't unreasonably block neighbors' lake views. |
| Boathouse | One boathouse in the lake setback, entirely above the high-water mark, with Building Board approval of its effect on neighbors' views. |
| Fence | Fences in the lake setback are allowed only along a bluff or for security of public property. |
| Path or stairs to the water | A walkway, stairway, pier or rail system up to 5 ft wide is allowed in the lake setback. |
| Code | Chapter 225, effective June 12, 2025. |
| Floodplain | Chapter 226 was updated for the 2025 maps and affects only Lake Mendota shoreline areas. |
Read the code · Village of Maple Bluff, 608-244-3048 · Remodeling in Maple Bluff
Village of Shorewood Hills Mendota
Houses stay behind the greater of 75 ft or a 'Special Lakefront Setback Line' drawn house by house in 2002.
| House or addition | The greater of 75 ft from the high-water mark or the Special Lakefront Setback Line, drawn along the backs of the houses on Lake Mendota Drive as of 2/1/02. If both neighbors are closer than the minimum, the required distance becomes the larger of their two yards. |
|---|---|
| Deck | Decks under 3 ft above grade can go to the water (0 ft setback). An attached deck 3 ft or more above grade counts as part of the house and must meet its setback. |
| Patio or terrace | Patios and terraces, pools, hot tubs and sport courts must be at least 25 ft from the high-water mark. |
| Boathouse | Allowed only on Lake Mendota lots, by conditional use: a Plan Commission hearing and a Village Board decision. |
| Fence | In setback, side and rear yard areas, at most 4 ft tall and 40% open. A fence permit is required. |
| Path or stairs to the water | Allowed, up to 5 ft wide within 25 ft of the water and 10 ft wide farther back. |
| Lot coverage | House plus accessory structures up to 25% of the lot in R-3. |
| Erosion | A permit for any land disturbance over 500 sq ft. |
Read the code · Village of Shorewood Hills, 608-267-2680 · Remodeling in Shorewood Hills
City of Middleton Mendota
30 ft from the water on most lakeshore lots, but 75 ft on land annexed after 1982.
| House or addition | 30 ft from the high-water mark on lakeshore lots. On shoreland annexed after May 7, 1982, the Shoreland Overlay sets 75 ft; lots in the Environmental Corridor Overlay keep development 50 ft back. |
|---|---|
| Deck | Non-elevated decks and patios can come within 8 ft of the high-water mark. |
| Patio or terrace | Patios can come within 8 ft of the high-water mark. |
| Boathouse | A permitted accessory structure, subject to the state boathouse rules. |
| Fence | At most 3 ft tall between the water and the yard facing the lake. |
| Path or stairs to the water | In the Shoreland Overlay, a 35 ft vegetated buffer with a viewing and access corridor up to 30 ft wide per 100 ft of frontage. |
| Code | Lakeshore rules rewritten by Ord. O1657, June 17, 2025. |
Read the code · Middleton Planning & Zoning, 608-821-8370 · Remodeling in Middleton
City of Monona Monona
The shore yard is measured from the old meander line, not the high-water mark, and only water-related buildings can go in it.
| House or addition | 50 ft from the meander line, which can rise to the average of the two neighboring houses, up to 75 ft. |
|---|---|
| Deck | The code lists no deck allowance in the shore yard, so a deck appears to need the house setback. Ask the Zoning Administrator. |
| Patio or terrace | Not addressed for the shore yard. Impervious surface is capped at 65% (lots over 10,000 sq ft) or 70% (smaller), and grade can't change more than 2 ft without a special exception. |
| Boathouse | Boathouses, boat shelters, landings and piers are the only accessory buildings allowed in the shore yard. |
| Fence | At most 42 inches tall and at least 10 ft from the high-water mark, with a fence permit. |
| Path or stairs to the water | Not addressed. Ask the Zoning Administrator. |
| Pools | In-ground pools at least 25 ft from the high-water mark and out of the floodplain. |
| Code version | Monona's code is on ecode360; this summary reflects the version dated July 21, 2025. |
Read the code · Monona Planning & Zoning, 608-222-2525 · Remodeling in Monona
Village of McFarland Waubesa
Every yard on the water is at least 40 ft, and decks can reach 10 ft into it but no closer than 30 ft to the water.
| House or addition | Yards on navigable water must be at least 40 ft, unless DNR or county rules require more. |
|---|---|
| Deck | Decks may project up to 10 ft into the waterfront yard, but no closer than 30 ft to the high-water mark. |
| Patio or terrace | Open terraces under 3 ft high are allowed in all yards. |
| Boathouse | No living space, and nothing built below the high-water mark. |
| Fence | No waterfront-specific fence rule found; the general fence rules apply (3 ft in a required front yard, 4 ft in a street side yard, 6 ft elsewhere). |
| Path or stairs to the water | Not addressed. Piers and boat shelters approved by the DNR are allowed in the waterfront yard. |
| Wetlands | A shoreland-wetland permit is needed before development in mapped wetlands of 5 acres or more. |
Read the code · McFarland Zoning, 608-838-3154 · Remodeling in McFarland
Town lots under Dane County shoreland zoning Mendota (Westport), Waubesa and Kegonsa (Dunn), Kegonsa (Pleasant Springs)
County shoreland zoning: 75 ft from the water, 15% hard surface within 300 ft, a 35 ft vegetated buffer, and a county permit for almost any work within 300 ft.
| House or addition | 75 ft from the high-water mark. If the nearest houses on both sides are closer than 75 ft, you may use their average, but no less than 35 ft. An existing house closer than 75 ft can be repaired, rebuilt or remodeled within its footprint, and raised up to 35 ft, without county approval under state law. |
|---|---|
| Deck | Decks count as impervious surface: 15% of the part of the lot within 300 ft of the water, or 30% with a mitigation permit. In the 75 ft setback, a small open-sided structure is allowed: at least 35 ft from the water, no more than 200 sq ft in total, with a buffer planted over 70% of the waterward half of the setback. |
| Patio or terrace | Patios, pavers, steps and retaining walls count toward the 15% impervious cap within 300 ft (30% with a mitigation permit). Any new or changed hard surface within 300 ft needs a county shoreland permit. |
| Boathouse | One boathouse in the setback, entirely above the high-water mark: up to 16 ft wide along the shore and 450 sq ft, no plumbing or cooking. A flat roof with no walls can be used as a deck. |
| Fence | Ask the county; state law lets certain fences stand in the setback. |
| Path or stairs to the water | A walkway, stairway or rail system up to 60 inches wide for access to the shore, with a shoreland zoning permit. |
| Permit | Shoreland zoning permit $150, with a licensed surveyor's plat of survey showing every hard surface. |
| Erosion | Any land disturbance within 300 ft needs a county shoreland erosion control permit. |
Read the code · Dane County Zoning, 608-266-4266
Piers, lifts and swim rafts
The DNR rewrote its pier and shoreline rule, NR 320, effective April 1, 2026, so older guides cite rules that have been replaced. (NR 320) A pier needs no DNR permit if it is: (Wis. Stat. 30.12)
- No more than 6 ft wide, floating or on posts or piles (not on fill or rock cribs), plus a loading platform up to 200 sq ft.
- No longer than needed to reach 3 ft of water at summer low levels, or enough depth to moor your boat or use a lift.
- Up to 2 boat slips for the first 50 ft of shoreline, plus 1 for each additional 50 ft.
- Inside your riparian zone and not in a DNR-designated special resource area.
Seasonal lifts and hoists next to your pier are exempt, and the DNR says lifts can stay in year round. A seasonal boat shelter (roof, no walls) for one boat, up to 30 ft by 14 ft, is exempt; a permanent one needs a DNR permit. Swim rafts within 200 ft of shore are exempt up to 200 sq ft and 38 inches high. (DNR Pier Planner 2026) Piers built before April 17, 2012 are generally grandfathered. Municipalities can add their own pier rules.
Riprap, seawalls and erosion control
- New riprap on an inland lake can be exempt up to 200 ft long: 6- to 48-inch stone, toe no more than 8 ft out from the high-water mark, no steeper than 1.25 to 1, and following the natural shoreline. (Wis. Stat. 30.12) Since April 2026 the site must also be a moderate- or high-energy shore, and the bank above the riprap must be replanted with native plants. (NR 320)
- Existing riprap: replacing up to 100 ft, or repairing up to 300 ft within its footprint, is exempt.
- Biologs and plantings using native plants are exempt if they meet the anchoring rules.
- Seawalls: a new seawall needs an individual DNR permit. Replacing an existing one can qualify for a general permit only in limited cases. (DNR)
- None of these exemptions apply on waters the DNR designates as Areas of Special Natural Resource Interest or Public Rights Features. Check the DNR's property lookup first.
- Erosion permits: in the county towns, any land disturbance within 300 ft of the water needs a county shoreland erosion control permit. (Ch. 11) Shorewood Hills requires one over 500 sq ft; Madison over 4,000 sq ft or when the city finds high risk.
Boathouses
No boathouse can be built over the water after December 16, 1979. An existing one over the water can be repaired only up to 50% of its assessed value, and can't get a floor added over a wet bay. (Wis. Stat. 30.121) On land, a boathouse entirely above the high-water mark can't be banned from the county setback, and its flat roof can be used as a deck if it has no walls or screens. (Wis. Stat. 59.692) Madison, McFarland and the county all bar living space in boathouses.
Floodplain and lake levels
Dane County Land & Water Resources runs the dams that hold the four Yahara lakes between summer limits set by the DNR in 1979. In 2018 Monona, Waubesa and Kegonsa all set record highs. (Dane County LWRD)
| Lake | Summer target (ft) | 1% flood elevation (ft) | Record high (ft) |
|---|---|---|---|
| Mendota | 849.6–850.1 | 852.8 | 852.74 (June 6, 2000) |
| Monona | 844.7–845.2 | 847.7 | 848.52 (Sept. 6, 2018) |
| Waubesa | 844.5–845.0 | 847.0 | 847.86 (Sept. 6, 2018) |
| Kegonsa | 843.0–843.5 | 845.8 | 845.74 (June 21, 2018) |
Elevations in NGVD29, as the county publishes them. FEMA maps use NAVD88, about 0.2 ft lower.
- In the mapped floodplain, additions, alterations and repairs, plus filling and grading, need a floodplain permit. (Dane County)
- If the work costs 50% or more of the building's assessed value, it's a substantial improvement and the whole house has to meet floodplain standards: in the county, the lowest floor 2 ft above the flood elevation. (Dane County Ch. 17)
- Madison moved its floodplain rules to a new Chapter 21 in 2025. (MGO ch. 21) Look up your lot on FEMA's Flood Map Service Center.
Wetlands and grading
Filling, grading or placing anything in a wetland needs a DNR wetland permit. (DNR) Grading more than 10,000 sq ft on the bank of a lake needs a DNR permit unless a county shoreland permit already covers it. Pea gravel or rock on the lakebed needs a permit, and sand blankets are generally not allowed. (DNR)
Frequently asked questions
How close to Lake Mendota can I build?
It depends on which municipality the lot is in. In Madison the setback follows your neighbors' houses, 75 ft if that doesn't apply, never under 25 ft. Shorewood Hills uses the greater of 75 ft or a line drawn in 2002. Middleton uses 30 ft, or 75 ft on land annexed after 1982. Maple Bluff draws a line for each lot on its zoning map. In the Town of Westport, county rules set 75 ft.
Do I need a permit for a pier?
Usually not, if it's an exempt pier: no more than 6 ft wide, on posts or floating, reaching only to 3 ft of water at summer low levels or enough depth to moor your boat, with up to two boat slips for the first 50 ft of shoreline. Since April 1, 2026 the DNR's pier rules are in a rewritten NR 320, and towns can add their own pier ordinances.
Can I put riprap on my shoreline without a permit?
Sometimes. New riprap up to 200 ft long can be exempt on an inland lake if it meets the size, slope and placement limits, and, since April 2026, only on a moderate- or high-energy shoreline with the bank above it replanted with native plants. It isn't exempt on waters the DNR designates as special resource areas. Check the DNR before you order stone.
Can I build a new boathouse over the water?
No. No boathouse may be built waterward of the high-water mark after December 16, 1979. On land, a boathouse above the high-water mark is usually allowed in the setback, with local limits.
Does the 100-year flood level affect my addition?
If the work is in the mapped floodplain, yes. Additions and alterations there need a floodplain permit, and if the work costs 50% or more of the house's assessed value, the whole house has to be brought up to floodplain standards.
My house is closer to the lake than the setback allows. Can I remodel it?
In the county towns, state law lets you maintain, repair, rebuild or remodel within the existing footprint, and add height up to 35 ft, without county approval. Cities and villages set their own rules for older houses inside the setback; Madison, for example, still requires Plan Commission review for additions over 500 sq ft.
Building on the lake with us
A lakefront project starts with the survey: where the high-water mark and the setback line fall on your lot, which approvals the project needs, and how much time a hearing adds. We sort that out before designing a deck, patio or addition. Decks · Additions and renovation · Remodel permits by town
We checked each code and the state and county rules in October 2026 and linked the sources. Some county Chapter 11 sections predate 2015 state law changes that limit them; where they conflict, state law controls. Confirm with the zoning office and the DNR before you build. This is a guide, not legal advice.