How we build every number

Principles

• Every number has a source and a vintage. Each figure carries a source chip or a title block naming the dataset and its date. The full list is on data sources.
• Missing means missing. When a source has no value for a place, the page says so. We never interpolate, estimate or borrow a neighbour’s value without saying so in the same sentence.
• Relative ratings stay relative. FEMA National Risk Index ratings compare a county (or census tract) with all others in the US. They are not probabilities of a loss, and we always say so next to them.
• No digital flood map is not no risk. Where FEMA’s National Flood Hazard Layer has no zone at a point, we say there is no digital map and link the FEMA Map Service Center. Any zone links FEMA’s map-change (LOMA) process.
• We do not sell leads. Nothing on a page changes with who pays us; see how we make money.

House Snapshot and county profiles

A ZIP code is resolved to counties through the Census Bureau’s 2020 ZCTA-to-county relationship file; when a ZIP spans several counties we show the one holding the largest share of the ZIP’s land area and let you pick another. Connecticut’s 2022 planning regions are matched through the towns they contain.

For each county we join: FEMA National Risk Index ratings (December 2025) for 18 hazards; OpenFEMA disaster declarations (counted once per disaster number); NFIP flood-insurance claims from the v3 dataset, by year of loss and by the rated flood zone on each claim; the IECC 2021 climate zone and Building America region from PNNL; the EPA radon zone; and the 50%-probability first and last 32°F dates from the NOAA 1991–2020 normals at the station nearest the county’s internal point (preferring a first-order weather station within 40 km). The station is always named.

With a street address, the Census geocoder returns the point and census tract. We then query FEMA’s flood hazard layer at that point and show tract-level NRI ratings. The address is not stored; the flood answer is cached for 24 hours by the point rounded to about 11 meters.

The Home Plan

The plan comes from a library of 103 tasks written by casaq. Each task has the months it is due, the Building America climate regions it applies to, optional system conditions (tank or tankless water heater, heat pump, boiler, septic, well, pets and so on), optional county hazard conditions (for example, hurricane tasks appear only where FEMA rates the county’s hurricane risk Relatively Moderate or higher), a severity, why it matters, and how to do it. Where an authority such as NFPA, EPA, DOE, CPSC or Ready.gov publishes the recommendation, the task cites it.

Freeze tasks move with your county: winterizing lands two weeks before the typical first freeze, and is dropped where a typical year has none. The calendar feed is an anonymous, signed link that contains only your ZIP and your answers; it has no account and no personal data, and each task keeps a stable ID so your calendar updates instead of duplicating.

When a page is kept out of search

Programmatic pages are indexable only when they pass five checks: enough real data points from at least two independent sources; a statistical floor (for county pages, an NRI rating other than “Insufficient Data” and at least three of five other sources); a decision delta (the page’s checklist differs from its parent hub’s by at least one item); unique text (no more than 60% five-word-shingle overlap with any sibling page); and freshness (the source is within its refresh window). Pages that fail still work for visitors but carry noindex, point their canonical to the parent hub, and are left out of sitemaps and hub links.

Corrections

Anyone can report an error on the corrections page. We check the report against the primary source and log accepted fixes with the date.

Information, not legal, insurance or engineering advice.