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Radon In Water Accessory for the RAD7


The RAD H2O is an accessory for the RAD7 that enables you to measure radon in water over a concentration range of from less than 10 pCi/L to greater than 400,000 pCi/L. By diluting your sample, or by waiting for sample decay, you can extend the upper range to any concentration.

The equipment is portable and battery operated, and the measurement is fast. You can have an accurate reading of radon in water within an hour of taking the sample. The RAD H2O gives results after 30 minutes analysis with a sensitivity that matches or exceeds that of liquid scintillation methods. The method is simple and straightforward. There are no harmful chemicals to use. Once the procedure becomes familiar and well understood it will produce accurate results with minimal effort.

By taking two simultaneous samples, analyzing one immediately, waiting a week or more and then analyzing the other, the radium (226Ra) content of the water may be calculated.

Product Highlights

  • Portable: Complete kit provided in fitted case; weighs just 13 lbs.
  • Automatic: Procedure is controlled fully by the connected RAD7.
    Printouts provide data on radon concentration in water.
  • Fast: Analysis can be completed within one hour of taking the water sample.
  • Accurate: The RAD H2O provides results as accurate as liquid scintillation.
  • Sensitive: More sensitive than liquid scintillation.
    Lowest limit of detection is 10 pCi/L (20 minute count).
  • Clean and Safe: Involves no hazardous materials or chemicals.
  • Proven: Used by individuals and labs throughout the world for over ten years.
  • Great Value: Practically no running costs.


A vial containing a water sample is set up in a closed air loop with the RAD7. The RAD7 pump operates automatically for five minutes to aerate the sample, distributing the radon that was in the water throughout the loop. The RAD7 waits a further five minutes while the 218Po count rate approaches equilibrium and then counts for four five-minute cycles. The radon concentration in the water is calculated directly.

RAD H2O Physical Specifications

RAD H2O Shipping Dimensions

19" x 16" x 8" (48 cm x 41 cm x 20 cm)

RAD H2O Shipping Weight

15 pounds (6.8 kg)



RAD H2O User's Manual (3D Printed Aerator Cap) (PDF)

RAD H2O User's Manual (Stainless Steel Aerator) (PDF)


RAD H2O Components (Illustration)

RAD H2O Configuration Diagram

Featured Articles

Product Comparison: Radon In Water Accessories (HTML)

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RAD H2O connected to RAD7 (not included)

RAD H2O case and contents

RAD H2O configuration diagram


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