Methodology

Same place.
Different records.
Visible limits.

How Is My ZIP keeps the source, geography, reporting period, and limitation beside every finding. The automated location briefing and the commissioned Property Decision File use different workflows because a ZIP is not an address and an address is not a parcel.

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Two workflows

Automation opens the area. Research checks the address.

Public ZIP and city briefings are generated from preprocessed national datasets and carefully labeled live sources. Custom property files begin with an exact address and add manual source checks that cannot be resolved reliably from a national ZIP index.

Public and account briefing

Location pipeline

ZIP or city entered
Census geography matched
County and reference point identified
National records assembled
Account modules loaded when requested
Source-labeled briefing rendered

Commissioned research

Property pipeline

Address standardized and geocoded
Parcel and jurisdictions identified
Scoped public-record checks performed
Findings and unresolved items separated
Geography and dates quality-checked
Property Decision File delivered

Sources

What the files use.

Slow-moving national records are preprocessed for speed. Current conditions are loaded on demand. Property-specific portals are checked manually only when they are included in a commissioned scope.

Public briefing core

FEMA National Risk Index

Provides: Official modeled natural-hazard values and ratings.
Geography: County-level.
Used for: Published heat, wildfire, drought, flood, and overall National Risk Index context.
Refresh: Rebuilt when FEMA source data changes.

OpenFEMA Disaster Declarations Summaries v2

Provides: Historical federally declared disasters.
Geography: County or designated-area records.
Used for: Federal declaration counts, categories, and recent history.
Refresh: Preprocessed and refreshed on a planned monthly schedule.

US Census ZCTA, county, place, and Gazetteer files

Provides: The geographic bridge between ZIP-like areas, counties, cities, and consistent reference points.
Geography: Census ZCTA, county, place, and internal-point geography.
Used for: Routing ZIP and city searches to the public records that actually exist.
Refresh: Updated when Census geography releases change.

Environmental receipts

EPA Toxics Release Inventory Basic Data

Provides: Facilities, listed chemicals, filing type, reported pathways, quantities, and EPA classification flags.
Geography: Facility coordinates near a Census ZCTA point in public briefings; address-geocoded point in custom files.
Used for: Industrial chemical filings and chemical-level record details.
Refresh: Currently uses reporting year 2024 and is rebuilt for each annual EPA release.

EPA Superfund geospatial and SEMS status data

Provides: NPL and Superfund Alternative Approach site coordinates, listing status, and human-exposure control status.
Geography: Straight-line proximity from the stated ZIP or address reference point.
Used for: Nearest-site records and proximity counts.
Refresh: Preprocessed from EPA snapshots so briefings remain fast.

EPA Map of Radon Zones

Provides: County Zone 1, 2, or 3 radon potential.
Geography: County-level; never a building measurement.
Used for: Regional radon potential and a prompt to test the building.
Refresh: Rebuilt when EPA updates its county zone table.

Account extensions

AirNow and National Weather Service

Provides: Current AQI observations, forecast conditions, and active alerts.
Geography: Nearby reporting area and NWS forecast point.
Used for: Current air and weather context.
Refresh: Requested live and cached briefly because conditions change.

EPA Enforcement and Compliance History Online

Provides: Regulated facilities, inspections, compliance status, enforcement actions, and reported penalties.
Geography: Facility proximity from the stated geographic reference point.
Used for: Compliance and enforcement records.
Refresh: Preprocessed from EPA's weekly ECHO Exporter download.

CDC PLACES ZCTA Data

Provides: Model-based adult prevalence estimates with confidence limits for selected health and access measures.
Geography: Census ZIP Code Tabulation Area.
Used for: Community health context, never individual diagnosis or causation.
Refresh: Preprocessed from the current annual CDC PLACES release.

USGS seismic models and earthquake catalog

Provides: Probabilistic reference-ground hazard curves and recorded earthquake events.
Geography: USGS model interpolation and a stated radius around the reference point.
Used for: Long-term seismic context and nearby recorded events.
Refresh: Model values are cached; recent events use a short refresh window.

EPA SDWIS / ECHO and Water Quality Portal

Provides: Possible public water systems, compliance records, and nearby environmental sampling inventories.
Geography: Census place matching for possible systems and a stated point radius for samples.
Used for: Separately labeled drinking-water and environmental-sampling context.
Refresh: Live responses are cached; source reporting schedules vary.

Custom property research

US Census Bureau Geocoder

Provides: A standardized address match and geographic coordinate.
Geography: Address-matched point, not a surveyed parcel boundary.
Used for: Anchoring address-level distance calculations and identifying the correct local systems.
Refresh: Run for the commissioned property file.

Official parcel, hazard, permit, and agency portals

Provides: Parcel identity, effective map references, local record history, agency jurisdiction, and direct verification paths.
Geography: Parcel, address, map panel, agency jurisdiction, or another explicitly stated unit.
Used for: Manual findings, unresolved questions, and the decision checklist in a Property Decision File.
Refresh: Checked during the commissioned research window and dated in the file.

Industrial and proximity records

Reference point first. Distance second. Conclusion last.

Reference point

Public briefings measure from a Census ZCTA internal point. Custom property files can measure from the Census-geocoded address point. Neither point is a parcel boundary or exposure pathway.

Form R

Detailed TRI Form R filings can include reported quantities for air, water, land, and off-site transfers. An off-site transfer is material moved elsewhere for management, not necessarily a release beside the facility.

Form A

Form A is EPA's shorter certification for an eligible lower-volume filing. Detailed release quantities are not published, and Form A does not mean zero releases.

Hazard is not exposure

Chemical classifications describe the reported substance. Exposure depends on quantity, pathway, transport, duration, distance, weather, and contact. TRI is not a sensor reading at a home.

Research status

No invented score. No silent blank.

Files distinguish a published value from an address match, a located source, an empty search result, and a professional handoff. Those labels prevent uncertainty from being rendered as certainty.

Published value

Shown as the agency published it

The file preserves the source value, classification, geography, and reporting period without converting it into our own verdict.

Address matched

Connected to the geocoded subject address

A custom file may anchor a record or distance to the Census-matched address point. That point is not a surveyed parcel coordinate.

Source located

The authoritative record system is identified

Some portals require a live parcel, owner, map-panel, or document search. The file identifies the correct source and the required check.

Not found

Not found in the checked source

This means the stated search returned no result at the stated time. It does not prove that no record exists anywhere.

Verify professionally

The public record has reached its limit

Title, inspections, disclosures, elevation, underwriting, legal interpretation, and physical condition require the appropriate professional.

Custom file workflow

What commissioned research adds.

A Property Decision File is priced around defined research work, not around access to a secret database. The scope determines which official systems are checked and which questions are carried into the final document.

View the sample file Ask about a property

01Normalize and geocode the subject address
02Identify parcel, county, agency, and map jurisdiction
03Re-anchor relevant facility distances to the address point
04Run scoped hazard, permit, assessor, and public-record checks
05Date every checked source and preserve direct references
06Separate findings, missing records, and unresolved questions
07Quality-check geography, wording, and professional handoffs
08Deliver a readable web file and printable research document

Limits

Where the record stops.

A useful file says what it cannot know. These are operating boundaries, not defensive fine print.

Search geography

ZIP codes are postal routes; Census ZCTAs are analytical approximations.
A city search uses an internal representative ZIP to route the briefing, while the report labels the selected city rather than presenting that ZIP as the city's one true ZIP.
County records can hide substantial variation inside a large county.
A custom address geocode is more specific than a ZIP point but is still not a surveyed parcel boundary.

Facilities and exposure

TRI, Superfund, and ECHO records do not prove contamination or exposure at an address.
TRI covers listed chemicals and covered facilities, not every pollution source.
Form A filings omit detailed release quantities and do not mean zero releases.
A permit is not a violation, and no listed violation does not prove complete compliance.
Agency reporting completeness varies by program, state, and facility type.

Models and mapped hazards

FEMA National Risk Index values are planning-model signals, not parcel forecasts.
A FEMA map lookup may require review of the effective panel, Elevation Certificate, LOMA, LOMR, or LOMR-F.
A mapped fire perimeter or hazard zone does not prove structure damage, mitigation, insurability, or future loss.
EPA radon zones describe county potential and cannot replace a building test.
CDC PLACES values are modeled population estimates, not diagnoses or evidence of causation.

Property decisions

Assessor, parcel, permit, zoning, title, and utility systems can disagree or update on different schedules.
Public-safety statistics describe the stated agency or jurisdiction, not an address-level safety rating.
Official registry searches remain on authoritative government portals; profiles are not copied into the file.
A Property Decision File cannot replace inspections, disclosures, underwriting, title work, legal advice, or physical verification.
How Is My ZIP is independent and is not affiliated with any government agency.

Freshness and performance

Slow data is prebuilt. Fast data is loaded when needed.

Disaster declarations, TRI filings, Superfund records, radon zones, ECHO exports, CDC estimates, and long-term seismic models change slowly. We preprocess or cache those sources so the core briefing does not wait for several national APIs.

AirNow, National Weather Service, recent earthquake, and selected water responses change more quickly and are requested only for signed-in readers as the relevant module is approached. Custom property sources are checked during the research window and show their access date in the finished file.

Dataset years do not move together. The reporting year or access date stays beside each record rather than being hidden behind a single “current” label.

Quality control

A clean trail is part of the deliverable.

Custom research is reviewed for address identity, geography, source authority, reporting date, language, and unresolved decision questions. Corrections should update the source trail, not merely the visible sentence.

The file should let another person answer:

Which source produced this finding?
What geography does it describe?
When was the source published or checked?
What does the record establish?
What does it not establish?
What should be verified next, and by whom?

Same place.Different records.Visible limits.