Residential Radon Testing LLC

Radon Testing. Most homes have radon. How much is in yours?

For Selling Agents

We save you time. We have SentriLock access so you do not have to meet us at the property. We will arrange entry into the home with the listing agent. You will be copied on all email communications and confirmations. Protect your buyers by including a radon testing contingency in your contracts. Testing can be performed 2 days before the home inspection to have results at the same time the home inspection is completed. 

We Can Make All The Arrangements

The Listing Agent is contacted, informing them of the impending radon test dates and times for both placement and retrieval. Selling agents are cc’d on all communications. 


We are an affiliate member of the REALTOR® Association of Prince William (PWAR) and have SentriLock access so you, the selling agent, do not have to meet us at the property to either place or retrieve the testing devices.  Access to a property is granted by the Listing Agent by providing us the CBS code (Call Before Showing) to the SentriLock  installed at the property. See instructions below on how to find your CBS code.

Your clients are invoiced by email where they can pay online using a credit card or a PayPal account.

How to Find Your SentriLock CBS Code

1. Log onto

2. From the Main Menu, on the left side of the screen, click on “Manage My Account”

3. On the “Manage My Account Page,” near the top of the screen, click on “Default Lockbox      Settings”

4. On the Lockbox Settings Page, third heading down at the center of the page, “Call Before      Showing (CBS) Settings” Find on the lockbox serial number that is at the property to find      the CBS code - (all your lockbox CBS codes are the same unless you individually changed      them)