Home/San Diego County, CA
California -- population 3,295,981

San Diego 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

San Diego County, CA hazard summary: FEMA National Risk Index rated Very High; EPA radon zone 3 of 3; most frequently recorded hazard is flood (153 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

San Diego County has 1,240,607 housing units. About 29% 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
9,883
2010-2019
80,790
2000-2009
148,459
1990-1999
143,180
1980-1989
230,751
1970-1979
269,345
1960-1969
143,963
1950-1959
124,703
1940-1949
39,037
1939 or earlier
50,496

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 San Diego County's overall natural hazard risk as Very High, relative to the rest of the country.

WildfireVery High
Inland FloodingVery High
EarthquakeRelatively High
LandslideRelatively High
Heat WaveRelatively High
Source: FEMA National Risk Index

Recorded Storm History (2015-2024)

NOAA recorded 443 storm events in San Diego 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
153
Flash Flood
89
Heavy Rain
83
Thunderstorm Wind
52
Debris Flow
24
Lightning
24
Hail
11
Funnel Cloud
7
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?How to Spot Polybutylene Pipes Before Buying a HouseCan You Get Home Insurance with Polybutylene Plumbing?

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 San Diego 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.