Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Radon

Explain Working Levels (WL) and Picocuries Per Liter of Air (pCi/L).

Radon test results may be reported in three different measures – picocuries per liter (pCi/L), Working Levels (WL) and becquerels per meter cubed (Bq/m3). If your test result is in pCi/L, the EPA recommends you fix your home if the radon level is 4 pCi/L (150 Bq/m3)or higher. If the test result is in WL, the EPA recommends you fix your home if the working level is 0.016 WL or higher. Some states require WL results to be converted to pCi/L to minimize confusion. While not commonly used in the United States, any radon level at or above 150 Bq/m3 should be reduced.

See our Radon Glossary of Terms  and the CDC/ATSDR’s Toxicological Profile for Radon: Chemical and Physical Information.

Find your state radon coordinator.

Radon

  • Indoor Air Quality Home Page
  • Radon Risks and Solutions
  • National Radon Action Plan
  • Standards of Practice
  • State and Tribal Indoor Radon Grants
  • Frequently Asked Questions
  • Radon Resources
Contact Us about Radon
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on November 26, 2024
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.