Try downloading this file to your desktop and then double-clicking it:
https://josm.openstreetmap.de/josm-tested.jar
Typically within the US overhead imagery (satellite or aerial) is accurate to within a few meters. It is much more likely that the data you are proposing to import is in error. You might try to get parcel data from the county in question and compare. Presumably, the state owns the SWA.