Many systems in WI are not in compliance with EPA standards due to the fact that WI is not a regulated state. There are techniques that can be implemented to further reduce your radon levels. Here are some things to look out for:
Radon fan in the house not on the outside or attic.
Radon fan is the wrong size and could be costing you extra in electrical costs.
No gauge on the venting that shows the vacuum pressure of the existing radon system.
Discharge pipe is not 2 feet above a window, 10 feet away, 10 feet above grade, and at least 12 inches above the eave.
Wrong thickness of venting is installed. Many companies have installed schedule 20 pvc instead of schedule 40 and this needs to be addressed.
Sump lid is not see-through and it is caulked down which can be a major inconvenience if the sump pump needs maintenance.
To be replaced in the event of an emergency.
Electrical may not be up to code. If the fan is on the exterior of the home there needs to be an on/off switch in sight of the fan and within 6 feet. If the fan is in the attic, a receptacle needs to be within sight and 6 feet from the fan.
There needs to be fire collars where the venting penetrates a fire wall such as drywall in the garage.
System components are not labeled correctly which can run the risk of a plumber using it as a drain or vent.
Check valve needs to be installed if venting is routed into the sump lid.