Residential, Commercial & Industrial Indoor Air Quality Assessments, Testing and Recommendations

Radon Assessment, Testing and Reporting

Radon Testing, Reporting & Radon Mitigation System Design


Radon is an odorless, colorless radioactive gas that can build up in structures and enter the lungs with the potential to emit alpha particles that cause lung cancer. The average indoor radon level is estimated to be about 1.3 picocuries per liter (pCi/L); roughly 0.4-pCi/L of radon is normally found in the outside air. EPA recommends radon mitigation if the average annual radon levels in a structure is 4-pCi/L or more. EPA states that every home should be tested for radon gas levels.

Radon Zone mapping & Geology

Radon gas levels are a function of the underlying geology of an area and the construction style of a structure. Rincon and Monterey Shale’s are Uranium rich bedrock and prominent rock types in Santa Barbara County. Uranium 238 (U-238) that emanates from bedrock decays into Radon Gas (Rn-222). For this reason, Santa Barbara County is considered a high radon zone.

The Santa Barbara County Radon Zone Map prepared by the California Department of Conservation of Mines & Geology for the State of California Department of Health Services shows high, moderate and low potential radon zones within Santa Barbara County. Wood Environmental has funded the Radon Map of Santa Barbara IOS app that can now be downloaded for free to your iPhone and iPad from the app store. This app has touch screen and search features that allow a user to input any address to determine the radon zone for that location.

Radon Testing

Certification is required for any business that provides radon services through the California Dept. of Public Health: California Certified Providers for Radon Services. Insure your radon services are provided by certified individuals

Short Term Radon Measurement Testing – EPA Real Estate Transaction Protocol requires testing for a minimum of 48 hours under closed house conditions. The structure should be closed 12 hours prior to testing and for the duration of the testing period with normal entry and exit acceptable. At a minimum, the lowest livable level of the structure should be tested.

Long Term Radon Measurement Testing – is conducted utilizing a unique test device under normal living conditions for a minimum of 3 months to a maximum of 1 year. This method is most common for home owners.

Continuous Radon Monitor Testing & Reporting - Wood Environmental utilizes Continuous Radon Monitors that collect up to five days of hourly averages and provide instantaneous results. The results are interpreted in a report that is issued with conclusions and recommendations based on the radon levels detected.

Radon Testing in Multi-Family Dwellings, Large Buildings & Schools – EPA has established a new protocol for radon testing in large buildings and schools. Wood Environmental is certified in large building measurements.

Radon Mitigation

Radon Mitigation Design in New Construction – The most cost effective radon mitigation system is one that is installed during construction in high radon zones. Wood Environmental is a certified Radon Mitigation Designer and can provide a plan for a built in system based on the architectural plans.

Retrofit Radon Mitigation Systems – Are very common and usually cost from $2,000 to $4,000 for a permanent fix depending on the construction type utilizing:

Sub Slab Depressurization – Bore 3 to 4“ hole through slab; attach 3 or 4“ PVC piping to fan system to pull sub surface soil gas up and out of the structure.

Sub Area Membrane Layer – Place 6 to 12 mil plastic in sub area with perforated PVC ducting attached to fan system under membrane layer.

Contact Wood Environmental for Certified Radon Mitigation Contractor referrals.

Post Radon Mitigation Testing

  • EPA requires a retest a minimum of 24 hours following installation of a mitigation system prior to occupancy.
  • EPA recommends testing an installed mitigation system every 2 years to insure efficiency.
  • Long Term Testing is recommended following radon mitigation.

WOOD ENVIRONMENTAL Radon Services Certifications

  • Wood Environmental Certification #RT 106128 - National Radon Proficiency Program, Residential Measurement Tester. NRPP List of Certified Radon Testers.
  • Design of Radon Control Systems in New Construction;
  • Radon in Soil Testing for New Construction; and
  • Radon Surveys in Multi-Family, Large Buildings & Schools.