For the past 13 months, we have been using a basic sediment filter and I have been changing the cartridge every three months. At those intervals I would find a fair amount of sand in the bottom of the filter housing -- probably about a half teaspoon. Recently in an effort to get all of the water out of the filter before storing it for the drive to our next location I have been opening the filter housing to dump excess water. Each time I do that I find some sand particles. I have to conclude from this that campground water -- while safe to drink -- contains more sediment than we would think.
It goes without saying that it is better to keep this sediment out of our faucet and shower screens.