Cost segregation in Door County, WI.

Door County is a seventy-mile peninsula with Green Bay on one side and Lake Michigan on the other, and the two sides behave differently enough that they are almost separate markets. The bay side — Egg Harbor, Fish Creek, Ephraim, Sister Bay — has the villages, the harbours, the sunsets and the higher prices. The lake side — Baileys Harbor, Jacksonport, the Cave Point stretch — is quieter, cooler, and cheaper on comparable water.

What makes Door County interesting on a cost segregation basis is unglamorous: the land share is moderate. Waterfront here does not carry the 40%-of-price land allocation that an Oregon oceanfront or a Cape Cod bayfront does, which means more of what you buy is depreciable improvements. The modelled example below reclassifies at 26.8% of basis, toward the top of the range we see across destination markets, and that is a structural feature of the market rather than an artifact of a favourable assumption.

• $145,505 accelerated into 5-, 7- and 15-year property
• $141,316 additional Year-1 depreciation
• $52,287 estimated Year-1 federal tax at the 37% bracket

Want a number for a specific Door County property? Use the calculator. It is pre-set with property-type defaults you can adjust to match your basis and bracket.

Cost Segregation in Door County, WI

Door County Investment Snapshot

• Representative price range $375K–$600K (Sturgeon Bay, inland, lake-side cottage); $600K–$1.1M (village-adjacent, water-view); $1.2M–$3M+ (bay-side waterfront, Ephraim and Fish Creek frontage)
• Season strong May through October, a distinct fall-colour peak, and a small but real winter market
• Common property types 3–5BR peninsula cottage, bay-side waterfront house, village condo, Washington Island property, Sturgeon Bay year-round house
• Wisconsin income tax graduated to 7.65% top marginal rate
• Bonus depreciation Wisconsin does not conform to federal §168(k)
• Lodging tax municipal room tax on short-term stays, varying by village, plus state sales tax
• Typical land share 20–30% of price, lower than most waterfront destination markets
• Representative Year-1 federal benefit $26,000–$105,000 depending on basis and finish

The Door County Market

Sister Bay and Ephraim anchor the upper bay side. Ephraim is the postcard village — white clapboard, no alcohol sales until relatively recently, the harbour and Eagle Bluff. Sister Bay is the larger commercial centre with the marina and the goat-roofed restaurant everyone photographs. Waterfront here runs $1.2M–$3M; village-adjacent water-view $600K–$1.1M.

Fish Creek and Egg Harbor sit just south, with Peninsula State Park between them — the state’s most-visited park, and the reason Fish Creek holds occupancy through shoulder season. Similar pricing to Ephraim, slightly deeper inventory.

Baileys Harbor and the lake side are the quieter half. Lake Michigan water is colder and the shore rockier, with Cave Point and the Ridges Sanctuary as the draws. Prices run meaningfully lower for comparable frontage, $450K–$1.2M, and the rental season is a touch shorter.

Sturgeon Bay is the county seat and the only real year-round town — shipbuilding, a working canal and bridges, and a housing stock priced for residents rather than visitors at $250K–$550K. Rental economics are weaker but so is the entry price, and a Sturgeon Bay property can run a mixed short-term and long-term model.

Washington Island, across Death’s Door passage by ferry, is its own thing entirely: cheaper, seasonal in the strict sense, and operationally demanding because everything arrives by boat.

Regulation here is municipal and varies by village. Several Door County municipalities have adopted short-term rental licensing and some have density or spacing rules. Wisconsin state law constrains how far municipalities can go — a municipality generally cannot prohibit short-term rental outright, though it can license and regulate, and can restrict rentals shorter than seven consecutive days in some circumstances. The practical upshot is that the rules are looser than in a capped market like Cannon Beach, but they are still village-specific and worth confirming at the address.

Why Cost Segregation Hits Different in Door County

The land share is moderate, and that is the headline. Waterfront destination markets usually punish the reclassification percentage because so much of the price is dirt. Door County is the exception in our set: at 20–30% land, a larger share of the purchase price is depreciable improvements, and the reclassification percentage comes in correspondingly higher. The modelled example runs 26.8% — compare 22.2% on a Cannon Beach oceanfront and 22.6% on a Cape Cod village property.

Shoreline structures are substantial and are 15-year property. Bay-side and lake-side lots frequently carry engineered stairs down a bank, permanent dock cribbing and foundations, boat hoists on dedicated service, seawalls and riprap where the shore is actively eroding, and the drainage work that protects a bank from runoff. On the lake side, where storms come in hard off Lake Michigan, shore protection is often recent and well documented.

Almost everything outside Sturgeon Bay is on private well and septic. A well with pump and pressure equipment and an engineered septic system sized for a 4- or 5-bedroom rental are both meaningful land improvements, and both are routinely omitted from studies that work from a purchase price rather than a site inspection.

Seasonal properties carry winterisation infrastructure that a year-round house in a warm market does not: heat tape, frost-protected plumbing runs, dedicated shutoffs and drain-downs, and in many cases a generator. These are worth identifying rather than absorbing into the structural shell.

Fall is a real second peak. Door County’s autumn colour season fills weeks that most northern lake markets lose, which means more annual turnover, faster wear on soft goods and floor coverings, and a 5-year bucket that replenishes more often than the calendar would suggest.

Worked Example — Door County

A 4-bedroom waterfront peninsula cottage near Sister Bay, roughly 2,200 square feet, built in 2001, acquired for $725,000 and placed in service in March 2026. Land is taken at 25% of price. Depreciable basis lands at $543,750.

Running that property through our engine produces $145,505 of reclassified property, or 26.8% of depreciable basis:

Under 100% bonus depreciation the additional Year-1 deduction is $141,316 — the Year-1 deduction with the study minus the Year-1 deduction without it, so the 27.5-year structural portion that would have depreciated anyway is already netted out. At a 37% federal bracket that is $52,287 in Year-1 federal tax.

Note the 15-year figure is modest relative to the 5-year figure. That reflects a modelled property without significant shoreline structures. A lot with engineered bank stairs, permanent dock cribbing and a seawall would shift meaningful dollars into the 15-year bucket and raise the total — which is exactly why a site inspection matters more here than in a market where every property has the same flat lot.

What is real and what is assumed. The split is a real engine run at the same code that produces a delivered study. The inputs are a representative Sister Bay-area cottage, not a specific address.

Who Is Doing This in Door County

The Chicago and Milwaukee buyer is the backbone of this market. Milwaukee is under three hours, Chicago about five, and Door County has been the Upper Midwest’s summer place for a century. This buyer typically holds one property, uses it several weeks, and rents the rest — so §280A personal use is the first thing to model.

The Madison and Twin Cities buyer shows up more on the lake side and in Sturgeon Bay, at lower entry points and with a more rental-driven thesis.

The multi-property peninsula operator holds three to eight cottages across the villages, often self-managing with a local cleaning company. This is the cohort where the Form 3115 lookback tends to be the larger opportunity, because the older holdings were bought before anyone mentioned cost segregation.

WI Tax Considerations

Wisconsin levies a graduated income tax reaching 7.65% at the top bracket.

Wisconsin does not conform to federal bonus depreciation under §168(k). Wisconsin decoupled and requires depreciation computed under the federal rules in effect on a fixed prior date, which excludes current bonus. The practical effect is the familiar one: the full federal Year-1 deduction is available, while the Wisconsin deduction follows a regular schedule, so the state benefit is spread across the recovery period rather than taken up front. Deferred, not lost. The Year-1 figure on this page is a federal number and should not be grossed up by 7.65%.

Door County municipalities levy room tax on short-term lodging, with rates set at the village level, and Wisconsin sales tax applies to short-term stays. Both are collected from the guest and remitted.

The Wisconsin-specific point worth raising with your CPA: state law limits how far a municipality can restrict short-term rental, but it also permits municipalities to require licensing and, in defined circumstances, to regulate rentals of fewer than seven consecutive days. If your §469 analysis depends on an average guest stay of seven days or fewer, and your village’s rules push you toward seven-night minimums, those two things interact directly. It is a rare case where a local ordinance can move a federal tax conclusion, and it is worth checking rather than assuming.

Common Door County Investment Properties

• The bay-side waterfront cottage, $1.2M–$3M, Ephraim, Fish Creek, Sister Bay frontage, heaviest shoreline site work
• The village-adjacent water-view house, $600K–$1.1M, best balance of rate and reclassification percentage
• The lake-side cottage, $450K–$1.2M, quieter, cheaper on comparable water, shorter season
• The Sturgeon Bay year-round house, $250K–$550K, mixed short- and long-term model
• The Washington Island property, lowest entry, strictly seasonal, operationally demanding

Depreciable Features We Commonly See on the Peninsula

Full furniture packages sized to bedroom and bunk count. Kitchen appliance packages on a short replacement cycle under summer-and-fall turnover. Floor coverings — carpet and luxury vinyl plank are 5-year and get replaced often. Hot tubs on dedicated electrical. Decorative and exterior lighting. Decking and railings, frequently composite on newer work. Engineered stairs and landings down a bank. Permanent dock cribbing and foundations, and installed boat hoists with their service. Seawalls and riprap. Crushed-stone and asphalt drives. Fire pits and patio hardscape. Irrigation and landscape. Private wells with pump and pressure equipment. Engineered septic sized for rental occupancy. Detached garages, bunkhouses and sheds. Winterisation infrastructure including heat tape and dedicated shutoffs. And on any recently renovated property, everything the invoices itemise.

What People Worry About (and What Actually Happens)

“My village has a seven-night minimum.” Then the §469 short-term rental exception may not be available to you, because that exception turns on an average guest stay of seven days or fewer. This does not affect whether a cost segregation study is accurate — the deductions are real either way — but it changes whether the losses can offset non-passive income. Confirm your village’s rules and take them to your CPA before ordering.

“Wisconsin doesn’t conform. Is it still worth it?” Yes. The federal deduction is the larger one and is unaffected. Non-conformity defers the state portion across the recovery period.

“I bought in 2020.” A Form 3115 change in accounting method claims the missed depreciation as a current-year catch-up without amending prior returns. For a property held six years this is frequently the bigger opportunity.

Why Cost Segregation Works for Door County Seasonal Rentals

Door County rentals mix summer weeks with two- and three-night shoulder-season and fall-colour stays, which for most properties puts average guest stay under seven days. That places a property inside the short-term rental exception under §469 — not automatically a passive rental activity, so an owner who materially participates may be able to apply losses against non-passive income. The caveat above is specific to this market and genuinely matters: if your village imposes a seven-night minimum, the arithmetic changes. Whether your participation and your average stay clear the tests is a question for your CPA.

Who This Example Applies To

The worked example assumes a 37% federal bracket, 100% bonus depreciation, a March 2026 placed-in-service date, and a 25% land share. At a 32% bracket, scale the Year-1 federal figure by roughly 0.86. With significant shoreline structures, expect a larger 15-year bucket and a higher total.

Compare: Door County Properties at Different Price Points

Rows other than the modelled one are indicative ranges scaled from that run, not separate engine runs.

Frequently Asked Questions

Does Wisconsin conform to federal bonus depreciation? No. Wisconsin computes depreciation under federal rules in effect on a fixed prior date, which excludes current bonus, so the state benefit is spread across the recovery period rather than taken in Year 1.

Why is Door County’s reclassification percentage higher than coastal markets? Land share. At 20–30% of price in land — versus 30–45% on the Oregon coast or Cape Cod waterfront — more of the purchase price is depreciable improvements, so a larger percentage reclassifies.

Is a dock depreciable? Permanent cribbing, foundations and installed hoists are generally 15-year land improvements. A seasonal removable dock is treated differently. A study should distinguish them rather than lumping them together.

Does a seven-night minimum change my study? It does not change the study. It may change whether the §469 short-term rental exception applies, which affects how the resulting losses can be used. That is a CPA question and it should be settled before you order.

What about Washington Island? The study works identically. The practical considerations are logistical — ferry-dependent access affects renovation costs, furnishing delivery and management — rather than tax ones.

Learn More About Cost Segregation

• How cost segregation works
• Bonus depreciation by state
• The Form 3115 lookback
• Cost segregation calculator

Ready to See Your Actual Door County Numbers?

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CPA use note: These figures estimate the size of the depreciation deduction. Whether the loss is usable in the current year depends on passive-activity rules, STR material participation, REPS status, entity structure, depreciable basis, and state conformity. Your CPA decides how and when it is applied. Specialty and site components (equipment, casework, docks, pools, arenas, tenant improvements, and similar) are only classified when you own them and they are included in the depreciable basis being studied.