Home/Orange County, CA
California -- population 3,183,647

Orange County, CA Property Research

Real data from four public sources, not an internal estimate: the EPA's radon zone classification, Census housing-age records, FEMA's natural hazard risk index, and NOAA's recorded storm history for this county. Every figure below links to where it actually comes from.

Hazard Summary

Orange County, CA hazard summary: FEMA National Risk Index rated Very High; EPA radon zone 3 of 3; most frequently recorded hazard is flood (39 events, 2015-2024).

Radon Risk

Zone 3 -- low potential. EPA predicts an average indoor radon screening level below 2 pCi/L for this county.

This is a county-wide prediction from geology and soil data, not a measurement of any specific home -- EPA recommends testing every home regardless of zone. See our guide on negotiating radon mitigation after inspection.

Source: EPA Map of Radon Zones

Housing Age

Orange County has 1,138,473 housing units. About 35% were built in 1969 or earlier -- old enough that knob-and-tube wiring, lead-based paint, and galvanized supply lines are all realistic possibilities worth checking for, not just a general inspection line item.

2020 or later
8,626
2010-2019
89,663
2000-2009
96,132
1990-1999
124,450
1980-1989
166,373
1970-1979
255,130
1960-1969
205,271
1950-1959
142,382
1940-1949
22,061
1939 or earlier
28,385

Does knob-and-tube wiring have to be replaced before closing?

Source: U.S. Census Bureau, ACS 5-Year Estimates, Table B25034

Natural Hazard Risk

FEMA rates Orange County's overall natural hazard risk as Very High, relative to the rest of the country.

EarthquakeVery High
Inland FloodingVery High
WildfireRelatively High
LandslideRelatively High
Heat WaveRelatively High
Source: FEMA National Risk Index

Recorded Storm History (2015-2024)

NOAA recorded 119 storm events in Orange County between 2015 and 2024. This is actual event history, not a risk model -- the counts below are individually logged storms, not a prediction.

Flood
39
Heavy Rain
28
Flash Flood
26
Debris Flow
10
Thunderstorm Wind
9
Hail
3
Funnel Cloud
3
Lightning
1
Source: NOAA National Centers for Environmental Information, Storm Events Database

Guides Relevant to This County's Housing Stock

Does a Standard Home Inspection Check for Asbestos?What Is a Federal Pacific Stab-Lok Panel and Why Inspectors Flag It?Do Federal Pacific (FPE) Panels Affect Insurance Like Zinsco Panels?Will a Zinsco Panel Fail a 4-Point Inspection?Can You Get Home Insurance with Aluminum Wiring?How to Spot Polybutylene Pipes Before Buying a House

Get Your Free Property Report

BeforeRegret pulls live seismic hazard data, validates the address, and builds era- and county-specific inspection priorities and seller questions into one report -- with anything not yet independently verified clearly labeled, not guessed at.

Get Your First Report Free

This page reports what these four public agencies have published for Orange County as a whole -- it is not an assessment of any specific address or property, and does not replace a licensed home inspection, radon test, or insurance review for a specific home. Data last checked August 10, 2026.