Over the past 45 years, Wisconsin has seen a dramatic increase in damage caused by flooding, as the climate has warmed, extreme rains have become more common, and urban development has continued. Increased flooding, in turn, has resulted in larger payouts on flood insurance claims, as well as increased federal and state payments for disaster recovery. With projections suggesting that continued climate change will further increase the likelihood of extreme rains, federal, state, and local governments will need to deal with the consequences.
Long-term changes in rainfall intensity and continued urbanization and land use changes have led to more destructive flood damage across the state and spiking damage claims. This is a key takeaway from our analysis of data from the National Flood Insurance Program, which offers subsidized coverage to property owners and renters. This federal program helps cover part of the costs associated with rebuilding after disasters like the massive flooding in Milwaukee and surrounding communities that took place on Aug. 9 and 10 as a result of near-record rainfall.
Data from this program show that the past three decades have seen a massive jump in Wisconsin flood damage, with more than $40 million in flood insurance damage claims for Wisconsin property in the 1990s, 2000s, and 2010s. The claims peaked during the massive floods of 2008, causing nearly $50 million in damage to federally insured property statewide, though damage from the most recent August 2025 storm in the Milwaukee area may eventually surpass these totals. State and local governments receive federal payments to help repair damage to infrastructure like roads, bridges, and public buildings to help blunt the impact of these natural disasters. Local governments also receive payments from the state.
In this brief, we review data from the Federal Emergency Management Agency (FEMA) to understand both the extent of the damage from flooding around the state over time and the funds used to help pay for rebuilding efforts. We also review data from the state of Wisconsin to see how state resources have been used to address the impacts of floods. Finally, we review options to limit flood damage and mitigate flooding.
Spiking Flood Insurance Claims
Beginning in 1997, the state has seen a series of massive flooding events that resulted in spikes in total damage claims by flood insurance policyholders, as shown in Figure 1. These surges in claims occurred without a substantial increase in the number of policies held in the state. Each of these spikes was associated with extreme rainstorms, during the worst of which more than 10 inches of rain fell over the course of a few days. These storms caused rivers and streams to overflow their banks and destroy buildings and infrastructure and caused flash floods, where water that flowed off of roofs and pavement inundated buildings, roads, and bridges built in low-lying areas. Current projections show a substantially increased likelihood of days with heavy rains over the next 20 years in most of the state, making spikes in property damage more likely to occur in the future.
Figure 2 shows the distribution of flood damage claims around the state since 1978. Southwestern Wisconsin has experienced the most flood incidents, in part due to its steep topography and abundance of rivers, which can produce flooding in the valleys where many of the villages and cities have been built. This partially explains the high value of damage claims in counties in that area of the state despite their relatively small populations. As shown in Figure 3, Milwaukee leads in flood damage claims, but other smaller cities also saw millions of dollars’ worth of damage. The greatest number of policies are held by residents of Milwaukee and Dane counties, but on a per capita basis, Door County has the most flood insurance policies, at 60.3 per 10,000 people. Taylor County (6.5 policies per 10,000) and Menominee County (no policyholders) had the lowest participation rates.
Looking closely at the individual spikes in damage claims shows how these disasters unfolded — and the widespread impact these storms have had on the state.
1997 and 1998 – Milwaukee
Damage claims in 1997 and 1998 were the first in the state to exceed $10 million when adjusted for inflation. Most of the damage in these years, including destruction of more than 400 flood-insured primary residences in 1997 and another 350 the next year, was concentrated in the city of Milwaukee and its neighbors, with more than $10 million in damage claims in the city itself in each year. Massive rains caused flash flooding in low-lying areas, covering some streets with one to two feet of water and inundating buildings. The city’s three rivers also overflowed their banks in some areas, further damaging property and infrastructure.
Avoiding a repeat of the damage from these floods is part of the reason why the Milwaukee Metropolitan Sewerage District has made extensive investments in massive stormwater retention facilities. In recent years, the district has also invested in “green infrastructure” – such as strips of preserved land known as bioswales and the use permeable pavement and rain barrels – to help manage stormwater. As part of that strategy, they have also invested in preserving natural areas upstream from the city to limit flooding. The district also collaborated with the Milwaukee County Parks to use parkland to help limit flooding, and Forum research has explored additional opportunities for the two organizations to work together on that front. Since 1998, Milwaukee County has seen additional floods, but the August 2025 storm was the first to be comparable in scale to these events.
2008 – Southern Wisconsin
Damage totals in 2008 far exceeded all other years on record and were caused mostly by record rainfall – in some cases well over 12 inches in a 48-hour period – across southern and central Wisconsin in June of that year, resulting in more than $47.2 million in damage claims statewide. While cities across the state were impacted by these floods, Fond Du Lac ($5 million in damage claims) and Fort Atkinson ($4.7 million) were the hardest hit, and seven other communities saw more than $1 million each in flood insurance claims caused by both massive flash flooding in low-lying areas and a number of rivers overflowing their banks.
2018 – Dane and Sauk Counties
The most recent spike in our data, in 2018, was the second-largest on record. That year saw two major floods in August – later than most other similar events — with cities in Dane County among the most heavily impacted. Communities with the greatest damage claims that year included Mazomanie ($1.3 million) and Middleton ($1.1 million) in Dane County, Elroy ($1.3 million) in Juneau County, and Reedsburg ($1.0 million) in Sauk County.
Flood Insurance Process
Flood insurance policies helped with rebuilding after these disasters, paying out millions to policyholders in the state. Created in 1969, the National Flood Insurance Program has two primary responsibilities intended to limit the impact of flooding nationwide. One component ensures access to flood insurance, especially to people in flood-prone areas. Thousands of people in Wisconsin utilize this option, holding more than 10,600 individual policies covering more than $2.5 billion of property — a small portion of the nationwide total of nearly 4.7 million policies covering property valued at $1.3 trillion. Most of these policies are held by people in hurricane-prone states like Texas, South Carolina, and Florida. They were created to assist people who could no longer insure their homes and businesses against flooding because private flood insurance is generally not available.
Insurance through the program is mandatory for many property owners in areas designated as being at risk for flooding, as defined by floodplain maps created by FEMA officials using data on rainfall and topography. Most other property, regardless of where it is located, is also eligible for flood insurance, though only 4% of homeowners nationwide have these policies. As a result, the cost of fixing most flood-related damage falls on property owners.
Policies are managed by both FEMA and private insurance companies and require premium payments like other insurance policies, but these premiums are subsidized by the federal government. Insurance costs to policy holders vary according to the risk of flooding in a specific location, property value, and other factors. Recent efforts by FEMA have changed how premium prices are set, based on property-specific risk assessments instead of flood maps alone. As of 2023, the median flood insurance policy for a single-family home in Wisconsin cost $804 annually, just above the national average of $786.
The second component of the program is a nationwide requirement that local governments adopt floodplain management standards limiting construction in flood-prone areas, as designated by the agency through the floodplain mapping process. These standards are intended to limit the amount of property at risk of flooding in the future. Communities must adopt these standards so that their residents are eligible for flood insurance policies.
Floodplain maps are created in collaboration with local communities and are updated periodically by the agency. While FEMA is responsible for creating the maps, state and local governments are ultimately responsible for enacting them at the local level. State and local officials are also responsible for enacting other land use control laws that set standards for development in floodplains. Because changes to floodplain maps can limit where development can occur in a community and can lead to additional costs to homeowners, changes to the maps can be controversial and require public outreach.
The recent tragedy at Camp Mystic in Texas shows the importance of accurate floodplain maps. In that case, some news reports have questioned whether buildings that housed the victims had been removed from the floodplain map there. With the increased likelihood of heavy rains over the coming decades, ensuring the accuracy of floodplains and limits to building in flood-prone areas will have increased importance.
Disaster Aid to State and Local Government
Flood insurance does not help pay for public infrastructure destroyed by these events. However, other federal resources are available to help communities rebuild through direct payments to state and local governments. For a community to be eligible for these funds, the president must first declare a natural disaster in the area. Once he or she does so, affected state and local governments can then apply for funds to pay for some of the costs of rebuilding infrastructure like roads and bridges. Frequently, these payments come as reimbursement for work already completed.
Floods are Wisconsin’s second-most frequent disaster declaration, having resulted in $123.7 million in inflation ajdusted payments for flood damage repair projects since 1999. Severe storms are the most frequent type, with payments for severe storms during the same period valued at $212.6 million. Federal disaster aid is vital to rebuilding efforts after major storms.
In addition to federal funding, the state offers two major programs that provide aid to help local governments rebuild after disasters like floods. One is specifically for roads damaged by floods, and the other is a general disaster aids appropriation through the state’s Department of Military Affairs. Aid through Military Affairs cover costs for local government repairs where federal funding is not available.
State aid to rebuild local roads after floods and other disasters is distributed through the state Department of Transportation. Cities, villages, counties, and towns can all apply for funds to repair roads or bridges destroyed by a natural disaster. Initially, this program only applied to flood damage, but that definition was expanded in 2017 to include other natural disasters. While this aid can be helpful, payments are capped at 75% of the total costs of replacing the destroyed roadway. As Figure 4 shows, state road damage aids tend to jump in response to major flooding events, while general disaster aids, which cover costs beyond road repair, don’t follow as closely with flood damage. This speaks to the impact floods can have on the state’s bridges and road network.
The amount of aid provided by these programs is typically much smaller than what is available from the federal government. For example, in 2018, when inflation-adjusted payments from the federal government totaled nearly $60 million and flood insurance claims topped $20 million, state payments through the Department of Military Affairs were only $1.8 million. While state costs for disaster aids have grown, they’re still a relatively small portion of the state’s $22.6 billion general tax revenue in 2026. However, these costs will likely grow over time, and state and federal aid do not cover all the expenses associated with damage to local infrastructure. So, state leaders may feel compelled to cover a greater share of flood-related costs as they grow with more frequent events.
Local Options for Limiting Damage
Municipalities manage stormwater and are responsible for both the amount of water and its quality. As our previous research shows, these costs are growing by more than 2.6% per year as of 2023. This money pays for pipes, detention ponds, seepage systems, wetlands, and other storage structures that help limit flooding and reduce its impact on streams, rivers, and lakes. Most of the increased costs are funded with stormwater impact fees charged to residents. Rising costs are the result of municipal expansion as development increases the footprint where stormwater management infrastructure is needed. Communities may also need to rebuild existing infrastructure to both accommodate heavier rains and replace aging assets.
In addition to building stormwater infrastructure, municipalities manage stormwater through ordinances that impose certain limits on the quality and quantity of water flowing from property developments, both during construction and after a new building is completed. Typically, these ordinances set limits for the total amount of water that can flow off of a specific property once development is complete. State law states that when a building is constructed, 90% of the water that seeped into the ground before it was built must continue to do so after construction. While stricter ordinances can help limit these impacts, they also make development more expensive, potentially increasing housing costs.
Often, these ordinances are designed with requirements for developments to make plans based on more or different rainfall amounts. State law sets a minimum for planning based on smaller, regular rainstorms known as two-year storms, while other communities like Madison and Milwaukee require planning for much larger 100- or 500-year storms based on their likelihood of occurrence. As the climate warms, these heavier storms occur more frequently, suggesting that it may be appropriate to design around them, though doing so can also increase project costs.
Conclusion
Current projections show that the frequency of heavy rain events and the potential for devastating floods will continue to grow over the coming decades. Property owners, along with state and local governments, will be on the hook for the costs of cleaning up and rebuilding after these floods occur. As costs grow, they may begin to stress state and local budgets, especially if state leaders decide to cover a growing share of the rebuilding costs. In addition, there are some questions about the federal government’s long-term commitment to covering these costs, which may push additional costs onto the state.
Floods will continue to happen despite our best efforts, but local governments have some tools to help limit their impacts, including both stormwater infrastructure and management standards. Infrastructure can be expanded to handle increasing rainfall, but the fees that fund that construction would have to rise to cover the growing costs.
Regulations to limit where buildings can be built or changes to how they’re built could reduce the impact of flooding but may also raise the cost of construction. These requirements may also limit the pace of housing construction, which is a major concern for many state residents. Going forward, local governments may need to find strategies to allow for the development of needed housing and commercial buildings while controlling the additional infrastructure costs and flooding it can generate.