Vendor-neutral facts on basements, foundations, water and soil risk — every figure sourced to a public authority (U.S. Census Bureau, EPA, FEMA, USGS, ASCE).
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These statistics are compiled from U.S. government and professional-body sources, for research and education. Figures that are contested in the literature are given as a sourced range. Free to cite with a link to this page.
Only about 16–17% of new U.S. homes are built with a basement — roughly 73% are slab-on-grade — and basements are concentrated in the colder North (New England ~67%, West North Central ~62%).
Source: U.S. Census Bureau & HUD, Survey of Construction (2024–25)
The U.S. EPA estimates about 1 in 15 American homes has an elevated radon level (at or above 4 pCi/L), and radon is often highest on the lowest level of a home — typically the basement.
Source: U.S. Environmental Protection Agency — A Citizen's Guide to Radon
FEMA estimates that just one inch of water inside a home can cause roughly $25,000 in damage — and standard homeowners insurance excludes flood damage.
Expansive (reactive) clay soils — which swell when wet and shrink when dry — occur across a large share of U.S. states and are concentrated in Texas, Colorado, California, Wyoming and the Dakotas.
Source: U.S. Geological Survey (USGS)
Expansive-soil damage is costly: widely-cited estimates range from about $2.3 billion a year (Jones & Holtz, 1973) to $15 billion or more in later estimates, and the ASCE is commonly cited that roughly one in four U.S. homes experiences some expansive-soil damage.
Source: American Society of Civil Engineers (ASCE) / published literature
Mold can begin to grow within 24–48 hours of water intrusion, so controlling basement and crawl-space moisture quickly matters.
Source: U.S. Environmental Protection Agency — Mold & Moisture guidance
More than one in five U.S. households depends on a septic system to treat its wastewater — and a failing system is a common, costly home problem.
Expansive, shrink–swell clay soils are a leading cause of cracked and sunken concrete — slabs, driveways and walkways — as the ground beneath heaves and settles with changes in moisture.
Source: U.S. Geological Survey (USGS)
We cite only vendor-neutral authorities and never imply their endorsement. Where a statistic is debated — for example the annual cost of expansive-soil damage — we present the published range rather than a single figure.