radon mitigation cost
1 Ground water wells can also be tested for radon, then, if needed, can get a water radon mitigation system installed. 2  Installing a water radon mitigation system runs from $1,000-$4,500, and maintenance runs $0 to $150 annually. 3  To find out about radon content in a city water system, call the local water provider. It's wise to retest a home's radon level every year or two after a mitigation system is installed. 2  Most radon mitigation systems include a fan, which will need to be replaced about every 5 years. 3  Expect to pay $250-$300 to have this necessary maintenance done.