I have never had any dirt or fine gravel in the gas station stuff I have used, but like others, I use multiple filters.... . none of the micropore filters we all use adequately filter out water, so I always catch a couple of oz in in a 2 oz jar looking for water, just like draining the sumps on full scale.....water with subsequent algae bloom while the jug sits in the hot summer sun will always ruin one's day........

Tom