Green Bay sits at the confluence of the Fox River and the Bay of Green Bay — the world's largest freshwater estuary — creating a water damage risk profile shaped by three forces that interact in ways unique to northeastern Wisconsin. The Fox River, draining a watershed that extends through the Fox Valley from Lake Winnebago, can flood when heavy rain or rapid snowmelt overwhelms its capacity (flood stage at 584.0 feet on the NOAA gauge). The Bay of Green Bay, controlled by Lake Michigan water levels, can push water back upstream into the Fox during northeast wind events — causing river flooding without any local rainfall. And Green Bay's extreme cold — over 150 nights below freezing per year, with frost depths reaching 15 to 38 inches — drives one of the most aggressive frozen pipe environments in the Midwest.
Call (888) 450-0858 for immediate 24/7 emergency water damage restoration in Green Bay, De Pere, Ashwaubenon, Howard, Suamico, Bellevue, Allouez, and throughout Brown County.
The Fox River enters Green Bay from the south, flowing through De Pere (where it narrows and drops over a dam) before widening through downtown Green Bay — past the City Deck, Leicht Memorial Park, and the CityDeck Landing development — and emptying into the Bay of Green Bay near the mouth. The East River joins the Fox near downtown, and Mahon Creek and several smaller tributaries add additional drainage throughout the city.
What makes Green Bay's flood risk unusual is the lake-river interaction. The Bay of Green Bay is essentially a large, shallow extension of Lake Michigan, and its water level rises and falls with the lake. When Lake Michigan levels are elevated — as they have been running slightly above normal for three consecutive years — the bay level restricts how quickly the Fox River can discharge. Strong northeast winds compound this by physically pushing bay water upstream into the Fox River, raising water levels along the river corridor independent of any rainfall event.
This is exactly what caused the significant April 2020 flooding: high bay levels combined with strong northeast winds pushed the Fox River to 584.3 feet — above the 584.0-foot flood stage — flooding the City Deck, portions of South Adams Street and Cass Street, and low-lying areas along both the Fox and East Rivers. Brown County Emergency Management mobilized disaster response teams, and the American Red Cross provided assistance to affected homeowners. Properties in these flood zones face Category 3 contaminated water requiring full flood damage cleanup protocols.
Green Bay averages over 150 days per year at or below freezing — with sustained stretches of -10°F to -25°F during January and February that penetrate deep into building envelopes. The 2025 winter produced frost depths of 15 to 38 inches — significantly deeper than 2024 — which has two consequences for water damage. First, the deep frost freezes plumbing at depths that milder winters do not reach, affecting underground service lines and basement-level plumbing in addition to the usual exterior wall and crawl space pipes. Second, when the deep frost thaws in spring, the frozen ground cannot absorb snowmelt, concentrating runoff into rivers and basements simultaneously.
Ice jams on the Fox River — where broken river ice accumulates at bridge piers, bends, and narrows — add a third winter flood mechanism. The NWS Green Bay office monitors ice jam potential throughout the winter, and an elevated risk remains until all river ice has cleared, typically by mid-April. During the 2025 spring flood outlook, several minor ice jams were observed on the Fox River and Wolf River systems upstream, and the overall flood risk was assessed with elevated concern due to the deep frost depths and above-normal streamflows in the Wolf River and Upper Fox River basins.
For immediate response steps when a pipe bursts, see our burst pipe emergency guide. For homes with aging plumbing at higher risk, see our water damage in older homes guide.
| Community | Primary Water Damage Risk | Notable Local Factors |
|---|---|---|
| Green Bay (Downtown, East Side, West Side) | Fox River flooding, sewer backup, frozen pipes | City Deck/downtown corridor directly on the Fox. East Side properties near East River face dual river flood risk. FEMA maps updated May 2023. |
| De Pere | Fox River flooding, frozen pipes | Fox River narrows through De Pere — concentrated flood risk. Dam operations affect water levels. De Pere received 0.90 inches in the June 2024 heavy rain event. |
| Ashwaubenon | Frozen pipes, storm runoff | Home to Lambeau Field and major commercial development. NWS Green Bay office (cooperative observer) located here. Newer construction but freeze-thaw pipe risk persists. |
| Howard, Suamico | Frozen pipes, spring runoff, East River tributary flooding | Howard received 2.13 inches in the June 2024 event — highest in Brown County. Rural-residential properties with private wells face contamination concerns during flooding. |
| Allouez, Bellevue | East River flooding, foundation seepage | East River Emilie Park selected for city's first nature-based flood mitigation project. Properties along East River corridor have chronic flood exposure. |
The Fox River has a unique environmental history that affects water damage restoration in flood scenarios. Prior to 1959, the paper industry discharged PCB (polychlorinated biphenyl) chemicals into the river. The subsequent EPA Superfund cleanup — one of the largest freshwater sediment remediation projects in U.S. history — removed contaminated sediment over more than a decade. The Fox River Trustees (U.S. Fish and Wildlife Service, Wisconsin DNR, the Oneida Nation, and the Menominee Nation) continue environmental monitoring.
For homeowners experiencing Fox River flood damage, the legacy contamination means that floodwater restoration should include awareness of potential sediment contamination — though the cleanup has dramatically reduced PCB levels. Restoration professionals working with Fox River floodwater should follow full Category 3 contamination protocols regardless, which already include the sediment handling and HEPA filtration procedures that address this concern.
Green Bay Inspection Division (permits + floodplain): (920) 448-3300
Brown County Emergency Management: (920) 448-6440
NWS Green Bay (weather/flood forecasts): weather.gov/grb
Fox River flood stage monitoring: NOAA gauge 040851385 at water.noaa.gov
Wisconsin contractor verification: dsps.wi.gov (Department of Safety and Professional Services)
FEMA flood map information: msc.fema.gov (maps updated May 2023 for Brown County)
24hr Water Damage Repair Emergency Line: (888) 450-0858
Green Bay faces three primary water damage threats. First, the Fox River — which flows through the center of the city before emptying into the Bay of Green Bay — floods when heavy rainfall or rapid snowmelt exceeds its capacity, with flood stage at 584.0 feet on the NOAA gauge. The East River, Mahon Creek, and smaller tributaries compound the problem during major events. Second, Green Bay's extreme cold — over 150 days per year below freezing — drives aggressive freeze-thaw pipe burst cycling, with deep frost depths (15 to 38 inches in 2025) increasing the risk of foundation seepage as ground thaws in spring. Third, Lake Michigan water levels directly affect the Bay of Green Bay and can back up the Fox River during northeast wind events, as occurred during the significant April 2020 flooding when high bay waters combined with strong winds to inundate the City Deck and riverside neighborhoods.
The highest-risk areas in Green Bay follow the Fox River and East River corridors. Properties near the Fox River from the Voyageur Park area through downtown (including the City Deck and the CityDeck Landing area) to the mouth at the Bay are within the FEMA Special Flood Hazard Area — updated maps were issued in May 2023. The East River corridor, particularly in the Allouez and Bellevue neighborhoods, is prone to flooding — the City of Green Bay selected East River Emilie Park as the preferred site for a nature-based flood mitigation project to address chronic flooding. De Pere, immediately south of Green Bay on the Fox River, shares the same flood risk corridor and is where the Fox River narrows before widening into the bay.
The Bay of Green Bay is the world's largest freshwater estuary, and its water level is controlled by Lake Michigan. When Lake Michigan levels are elevated — as they have been running slightly above normal for the past three years — the bay level rises, which slows Fox River discharge and increases upstream flooding risk. Additionally, northeast winds can push bay water upstream into the Fox River, raising river levels independent of rainfall. This wind-driven flooding can catch homeowners off guard because it occurs without any local precipitation event. The combination of high lake levels plus northeast winds plus spring snowmelt creates the highest-risk flooding scenarios for Green Bay properties.
Emergency water mitigation (extraction and drying) does not require a permit. Reconstruction work in Green Bay is permitted through the City of Green Bay Inspection Division — the same office that manages floodplain compliance. Contact the Inspection Division at City Hall to verify whether your property is in a FEMA Special Flood Hazard Area, which triggers additional permit requirements for reconstruction after flood damage. Wisconsin requires contractor registration through the Department of Safety and Professional Services (DSPS) — verify any restoration contractor at dsps.wi.gov. De Pere, Ashwaubenon, Howard, and other Brown County municipalities have their own building departments with separate permit processes.
Green Bay area restoration costs run approximately at or slightly below national averages due to lower labor costs in the northeastern Wisconsin market. A typical Class 2 clean water pipe burst costs $2,200 to $4,500 for mitigation. However, Fox River or East River flood damage involving Category 3 contaminated water costs significantly more: $8,000 to $16,000+ for residential properties requiring full demolition and decontamination. Winter pipe bursts discovered late (after a multi-day freeze) frequently escalate to Class 3 damage because the water runs undetected while homeowners are away — making response speed the most important cost variable. For detailed pricing, see our restoration cost guide.
Every hour of delay increases damage, cost, and mold risk. Call now for immediate help from an IICRC-certified restoration professional.