Radon · ZIP 97231
Radon in Portland (OR, NW Hills), OR
ZIP 97231 (Oregon) — radon summary sourced from EPA Radon Zones. Data lands this week as the EPA Radon Zones ingestion pipeline rolls out.
Last verified 2026-04-24 · methodology
What lands here
Pages show the county zone, what the classification means for home testing recommendations, and state-level supplementary data where available.
Source & refresh
EPA Radon Zones. Refreshed static 1993 baseline plus state-level supplementary updates. Stale data is flagged, never silently served. Primary source →
Limitations specific to this source
Radon is a regional indicator. Address-level radon measurement requires an at-home test kit (often free from state health departments).
Oregon context
Wildfire, Cascadia seismic, coastal flood
Oregon has high WUI wildfire risk in the Cascades + eastern + southern forests. Cascadia subduction zone shapes long-term seismic risk. Coastal FEMA VE/AE zones; Portland metro carries some LCRR obligations.
See Oregon state page for the full state-level rollup across all 12 dimensions.
Read more on radon
Editorial deep-dives explaining the source data, its limits, and how to read it.
EPA Radon Zones — what 1, 2, and 3 mean and when you should test
EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.
EPA SDWIS — how to read drinking-water violations and what they actually mean
Plain-English guide to EPA SDWIS drinking-water violations: health-based vs. monitoring vs. reporting violations, MCLs, and what triggers a public notice.
Radon and real estate — what disclosure laws and home tests actually require
What home sellers must disclose about radon by state, when home tests are required, and how to interpret radon-mitigation systems if a home you're buying has one.
Full dashboard for ZIP 97231
Radon is one of twelve dimensions zipradar federates per address. See the full federated summary for ZIP 97231:
Open Portland (OR, NW Hills), OR dashboard →