The American Community Survey (ACS) is the Census Bureau's ongoing household survey covering demographic, social, economic, and housing characteristics across all US geographies. For real estate analysis, the median household income data by CBSA (Core Based Statistical Area) is the key variable.
How ZipMarketData Uses ACS Data
ZipMarketData's pipeline downloads ACS 1-year estimates from the Census API for every CBSA in the US, covering 900+ metro areas. This income data feeds directly into the /affordability endpoint, enabling price-to-income ratios and affordability index calculations for any metro.
ACS 1-Year vs 5-Year Estimates
The Census publishes two ACS variants: 1-year estimates (more current, higher margin of error) and 5-year estimates (more stable, lower margin of error). ZipMarketData uses 1-year estimates for metros with sufficient sample size and falls back to 5-year estimates for smaller geographies.
Income Data Lag
ACS data is released approximately 12 months after the reference year — so 2024 income data becomes available in late 2025. ZipMarketData uses the most recent available ACS vintage and flags the reference year in API responses. In fast-growing metros, income growth may outpace what the data shows — adjust your affordability models accordingly.