Winds took part of the Chernobyl fallout to Finland. Especially the area where I live - traces of radiation can still be detected in local fish and mushroom...

Otherwise, if not living near heavy industry, I guess drinking rain water is a safe option. (I just checked wikipedia - it says that gaseous pollutions can spread hundreds of kilometres. So, that it the scale of radius when determining what means "near heavy industry".)

Here in Finland I've always been rather unworried with natural waters - practically speaking all of our lakes, rivers and brooks contain drinkable water. Some 500 metres away from my yard there is a natural spring, where fresh ground water comes to the surface. One can just go there and scoop drinkable water with a bucket.

(I've heard there are plans to privatise our ground waters, so that they can be mass bottled and sold for private profit. There is a broad opposition to such plans.)