How This Report Was Built
The Gwinnett County Water Damage Report draws on four independent public data sources, one proprietary field dataset, and direct expert testimony. Where findings depend on cross-source analysis, the calculation method is stated explicitly.
Primary Data Sources
NOAA Storm Events Database (2015-2024)
Severe weather event records for Gwinnett County, Georgia, including event type, date, location, narrative descriptions, and documented property damage figures. Used to quantify severe weather events, identify flash flood and thunderstorm wind events, and establish the subset producing confirmed structural impact.
FEMA National Flood Insurance Program Claims Data (2013-2023; 2016-2022)
Federal claims records used to establish that one-third of all NFIP claims nationally between 2013 and 2023 originated from properties outside designated high-risk flood zones. The 2016-2022 subset provided the average NFIP claim payout figure cited in the report.
U.S. Census Bureau American Community Survey, 2024 - Table B25034
Housing unit construction year data for Gwinnett County. Source for the county's total housing-unit count and the finding that 278,468 units were built before 2010.
Insurance Information Institute, 2025
Annual homeowner insurance claims benchmarks, including the 1-in-67 annual water damage claim rate, national average claim cost, and water damage's share of homeowner claims.
Water Pro Inc. Field Data
Observational data from more than 20 years of water damage restoration operations in Gwinnett County, provided by owner Andrew Foray. This data is proprietary and reflects direct field experience, not a published dataset.
Supporting Sources
Supporting sources include EPA mold guidance for the 24- to 48-hour mold colonization window, CPSC documentation for rubber washing machine supply hose replacement guidance, and Cox v. Shell Oil Co. class action settlement material for polybutylene pipe context.
Analytical Approach
The 5,240 annual Gwinnett claim estimate was produced by applying the Insurance Information Institute's 1-in-67 rate to the Census Bureau's 351,100 unit count. The $80.7 million economic impact figure multiplies that estimate by the $15,400 national average. Both are estimates, not audited totals.
Limitations
Storm damage figures reflect NOAA-documented events only; unreported or uninsured damage is not captured. Claim estimates are county-level projections based on national rates and may not reflect Gwinnett-specific insurer data. Water Pro field data represents one operator's experience and is not a statistically randomized sample.