Pennsylvania
General patterns from public USGS groundwater research, not a prediction for your specific well. Depth, local bedrock, and nearby land use matter more than the state line.
Wells drilled into granite or other radon-bearing bedrock, common across parts of New England and the Appalachians, are more likely to carry elevated radon in the water itself, separate from indoor-air radon.
Limestone and karst geology in parts of the region lets surface contamination (bacteria, runoff) reach groundwater faster than in areas with more soil filtration. Bacterial testing after heavy rain is worth doing more often here.
A test is the only way to know what's in your well. Already have results? Upload them and get every reading checked against EPA levels, free.