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.

These represent key takeaways from the Wisconsin Policy Forum’s recent analysis that includes 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, such as the massive flooding in Milwaukee and surrounding communities on Aug. 9 and 10 following near-record rainfall.

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. Data from this program (beginning in 1978) 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 each of the previous three decades: the 1990s, 2000s, and the 2010s.

Claims peaked during the massive floods of 2008, causing nearly $50 million in damage to federally insured property statewide, particularly in southern and central Wisconsin. However, damage from the most recent August 2025 storm in the Milwaukee area may eventually surpass these totals.

Our analysis looked at the distribution of flood damage claims around the state since 1978.  Southwestern Wisconsin experienced the most flood incidents during this period, 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 were built.

Current projections show that the frequency of heavy rain events and the potential for devastating floods will continue to grow over the coming decades, meaning that federal, state, and local governments will need to deal with the consequences. Local governments have some tools to help limit flood impacts, including both stormwater infrastructure and management standards. Infrastructure can be expanded to handle increasing rainfall, but revenues 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. However, such requirements may also raise the cost of construction and limit its pace – which could hinder their ability to alleviate Wisconsin’s widespread housing availability and availability challenges. Going forward, local governments may wish to find strategies to allow for development of needed housing while controlling the additional infrastructure costs and flooding it can generate.

This information is a service of the Wisconsin Policy Forum, the state’s leading resource for nonpartisan state and local government research and civic education. Learn more at wispolicyforum.org.