State Overview
CA
Select your county below to view itemized mitigation estimates, local labor rates, and EPA zone risk factors.
Alameda
Alpine
Amador
Butte
Calaveras
Colusa
Contra Costa
Del Norte
El Dorado
Fresno
Glenn
Humboldt
Imperial
Inyo
Kern
Kings
Lake
Lassen
Los Angeles
Madera
Marin
Mariposa
Mendocino
Merced
Modoc
Mono
Monterey
Napa
Nevada
Orange
Placer
Plumas
Riverside
Sacramento
San Benito
San Bernardino
San Diego
San Francisco
San Joaquin
San Luis Obispo
San Mateo
Santa Barbara
Santa Clara
Santa Cruz
Shasta
Sierra
Siskiyou
Solano
Sonoma
Stanislaus
Sutter
Tehama
Trinity
Tulare
Tuolumne
Ventura
Yolo
Yuba
CA Radon Levels by County
View EPA zone data and risk classifications
How to Test for Radon
Complete homeowner's testing guide
Why Does Cost Vary in CA?
Cost estimates across CA range due to local labor market conditions and specific EPA zone profiles. Foundation types (basement vs slab) also heavily impact material costs and permit requirements. Choose your specific county to narrow down your estimate bounds.