Metro Detroit Basement Risk Index

A free, public dataset scoring all 116 communities in metro Detroit (Wayne, Oakland, and Macomb counties) on basement-flood risk, built from U.S. Census housing data and City of Detroit flood records by Basement Risk Check, a southeast Michigan homeowner resource. Full report: https://basementriskcheck.com/report. Methodology: https://basementriskcheck.com/methodology. Current files and dated releases, each frozen at a permanent URL: https://basementriskcheck.com/data What is in this version. metro-detroit-basement-risk-index.csv: 116 communities, ranked, with the Basement Risk Index score, the share of homes built before 1960, median home value, scoring basis, a confidence grade and a link to each community report. detroit-flood-equity-by-zip.csv: the City of Detroit's water-in-basement report rate per 1,000 homes beside median household income and race, for 28 ZIP codes. metro-detroit-bri-2026-refresh.csv: old vs new score, rank and risk band for all 116 communities after the July 2026 rescore onto ACS 2020-2024. A data dictionary for each dataset, a README and the license. Headline finding. In metro Detroit, the communities most at risk for basement flooding are the oldest, not the wealthiest. Grosse Pointe and Novi have nearly identical median home values, but Basement Risk Index scores of 94 and 5, because what drives basement water here is housing age and aging sewer infrastructure, not income. Detroit's older neighborhoods carry real, documented risk: more than 13,900 water-in-basement reports in the City of Detroit's 311 record as of September 2026, and the June 2021 storms brought a federal disaster declaration. Method. The index is an honest hybrid. The two largest inputs are U.S. Census measures of housing age (share of homes built before 1960, and median year built). Detroit's score additionally blends in its real 311 water-in-basement records. Suburban scores are modeled from housing data and are labeled as modeled. They are not claims of observed flooding. Scores are rescaled 0 to 100 across the metro (median about 37). Sources. U.S. Census American Community Survey 2020-2024 5-year estimates (the index). ACS 2018-2022 5-year estimates by ZIP (the equity file's income and race). City of Detroit Improve Detroit / 311 water-in-basement service requests, 2023 to present. U.S. Census TIGER/Line boundaries. About this version. Version 2026.08 matches release 2026.08 on basementriskcheck.com/data. Version 1.0 (June 2026) carried scores from before the July 2026 rescore. License: CC BY 4.0. Please credit "Basement Risk Check" and link to https://basementriskcheck.com/report.