How to Evaluate Multiple Home-Safety Hazards Together
Data source: EPA drinking-water records, FEMA flood records, and U.S. Census ACS housing vintage
Updated August 6, 2026. ZipCheckup withdrew the earlier quantitative edition of this article during a full data-trust rebuild. Old rankings, totals, correlations, and cost estimates are not carried forward unless they can be reproduced from accepted source-bound evidence.
What this page answers now
A method for reviewing lead, flood, and housing-age evidence without treating an old composite count as a current fact.
The primary evidence family for this topic is EPA drinking-water records, FEMA flood records, and U.S. Census ACS housing vintage. Used within its published definitions, that evidence can show when independently measured hazards overlap at a defined geography.
What the data does not establish
The same records cannot prove that every property shares the overlap or substitute a ZIP pattern for inspection and testing. A nearby record is not automatically a property-level finding. A missing match is an unknown state, not a measured zero. Different geographic units must not be joined as if they described the same population.
A safer review sequence
- Identify the exact address, utility, facility, monitor, tract, or other unit that the source measures.
- Check the record date, reporting period, units, qualifiers, and coverage. “ND” means not detected at the stated reporting limit; it is not the numeric value zero.
- Keep source disagreement visible. If two official sources report different values, retain both with their dates instead of silently choosing one.
- Use the record as a screening lead, then verify each component separately, note its date and coverage, and investigate the address before combining signals.
- Do not treat a ZIP-level pattern as an inspection, diagnosis, legal determination, insurance decision, or guarantee.
Where the Home Safety Score fits
This topic may appear elsewhere on ZipCheckup as context, but it is not automatically a weighted score component. The current Home Safety Score uses four required inputs across three equally weighted domains: drinking-water compliance, with PFAS inside that domain; radon; and annual AQI. Missing required evidence produces an unavailable score, not a zero or an inferred value.
Why the previous numbers were removed
The retired edition mixed older data releases, legacy Home Safety Score logic, and derived aggregates whose complete input trail could not be reproduced under the current standard. Replacing one old headline number with another would repeat the same error. This edition therefore keeps only claims that remain valid without those retired calculations.
Data status
This page is a revalidated methodology and interpretation guide, updated 2026-08-06. It is not a new national ranking. Any future quantitative edition must publish its source versions, as-of dates, measured denominators, treatment of missing data, exact calculation method, and a reproducible release identifier.
Frequently Asked Questions
What can how to evaluate multiple home-safety hazards together establish?
It can show when independently measured hazards overlap at a defined geography. The conclusion is limited to the source, geography, period, units, and coverage shown with the record.
What does a missing record mean?
It means the source did not provide a matched measurement in the reviewed scope. It does not mean zero risk, no event, or a clean result.
How should I use this information for a home?
Use it as a screening lead: verify each component separately, note its date and coverage, and investigate the address before combining signals.