You cannot predict radon levels based on state, local, and neighborhood radon measurements. Do not rely on radon test results taken in other homes in the neighborhood to estimate the radon level in your home. Homes which are next to each other can have different indoor radon levels. It is possible for one home to have elevated levels while a neighboring home does not. Testing is the only way to find out what your home's radon level is. 

To get an accurate understanding of the Radon level in a home, long term testing of 90 days or more should be done, since levels in a home can vary greatly, going from safe to dangerous in short periods of time. The EPA and Surgeon General recommend testing all homes below the 3rd floor.

SHORT TERM TESTING

The quickest way to test is with short term tests. Short-term tests remain in your home for two days to 90 days, depending on the device. “Charcoal canisters,” “alpha track,” “electret ion chamber,” “continuous monitors,” and “charcoal liquid scintillation” detectors are most commonly used for short-term testing. Because radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to tell you your year round average radon level. If you need results quickly, a short-term test followed by a second short term test may be used. If you are doing a short term test lasting just 2 or 3 days, be sure to close your windows and outside doors at least 12 hours before beginning the test and keep them closed as much as possible during the test. You should not conduct short term tests lasting just 2 or 3 days during unusually sever storms or periods of unusually high winds. Heating and air conditioning system fans that re-circulate air may be operated. Do not operate fans or other machines which bring in air from outside. Fans that are part of a radon reduction system or small exhaust fans operating only for short periods of time may run during the test. The test kit should be placed in the lowest lived in level of the home, the basement if it is frequently used, otherwise the first floor. Place the kit at least 20 inches above the floor in a location where it won’t be disturbed, away from drafts, high heat, high humidity, and exterior walls. Sometimes short-term tests are less definitive about whether or not your home is above 4 pCi/L. This can happen when your results are close to 4 pCi/L. For example, if the average of your two short-term test results is 4.1 pCi/L, there is about a 50% chance that your year-round average is somewhat below 4 pCi/L.

If you prefer you can hire a qualified tester to do the testing for you. You can contact your "State Radon Office" about obtaining a list of qualified testers. You can also contact a private radon proficiency program for lists of privately certified radon professionals serving your area such as the "National Radon Safety Board" or the "National Environmental Health Association".