The contract
Ask the contractor to prepare a contract before any work starts. Carefully read the contract before you sign it. Make sure everything in the contract matches the original proposal. The contract should describe exactly what work will be done prior to and during the installation of the system, what the system consists of, and how the system will operate. Many contractors provide a guarantee that they will adjust or modify the system to reach a negotiated radon level. Carefully read the conditions of the contract describing the guarantee. Carefully consider optional additions to your contract which may add to the initial cost of the system, but may be worth the extra expense. Typical options might include an extended warranty, a service plan, and/or improved aesthetics.

Important information that should appear in the contract includes:

• The total cost of the job, including all taxes and permit fees; how much, if any, is required for a deposit; and when payment is due in full.
  
  
• The time needed to complete the work.
  
  
• An agreement by the contractor to obtain necessary permits and follow required building codes.
  
  
• A statement that the contractor carries liability insurance and is bonded and insured to protect you in case of injury to persons, or damage to property, while the work is done.
  
  
• A guarantee that the contractor will be responsible for damage and clean-up after the job.
  
  
• Details of any guarantee to reduce radon below a negotiated level.
  
  
• Details of warranties or other optional features associated with the hardware components of the mitigation system.
  
  
• A declaration stating whether any warranties or guarantees are transferable if you sell your home.
  
  
• A description of what the contractor expects the homeowner to do (e.g., make the work area accessible) before work begins.

Checking your contractor's work
Below is a list of basic installation requirements that your contractor should meet when installing a radon reduction system in your home. It is important to verify with your contractor that the radon mitigation standards are properly met to ensure that your radon reduction system will be effective. You can also check with your state radon office to see if there are state requirements that your contractor must meet.

• Radon reduction systems must be clearly labeled. This will avoid accidental changes to the system which could disrupt its function.
  
  
• The exhaust pipe(s) of soil suction systems must vent above the surface of the roof and 10 feet or more above the ground, and at least 10 feet away from windows, doors, or other openings that could allow the radon to reenter the house, if the exhaust pipe(s) do not vent at least 2 feet above these openings.
  
  
• The exhaust fan must not be located in or below a livable area. For instance, it should be in an unoccupied attic of the house or outside - not in a basement!
  
  
• If installing an exhaust fan outside, the contractor must install a fan that meets local building codes for exterior use.
  
  
• Electrical connections of all active radon reduction systems must be installed according to local electrical codes.
  
  
• A warning device must be installed to alert you if an active system stops working properly. Examples of system failure warning devices are: a liquid gauge, a sound alarm, a light indicator, and a dial (needle display) gauge. The warning device must be placed where it can be seen or heard easily. Your contractor should check that the warning device works. Later on, if your monitor shows that the system is not working properly, call a contractor to have it checked.
  
  
• A post-mitigation radon test should be done within 30 days of system installation, but no sooner than 24 hours after your system is in operation with the fan on, if it has one. The contractor may perform a post-mitigation test to check his work and the initial effectiveness of the system; however, it is recommended that you also get an independent follow-up radon measurement. Having an independent tester perform the test, or conducting the measurement yourself, will eliminate any potential conflict of interest. To test the system's effectiveness, a 2-7 day measurement is recommended. Test conditions: windows and doors must be closed 12 hours before and during the test, except for normal entry/exit.
  
  
• Make sure your contractor completely explains your radon reduction system, demonstrates how it operates, and explains how to maintain it. Ask for written operating and maintenance instructions and copies of any warranties.