Tiny rocks and such are pretty uncommon in the aerator of a brand new rig, however, construction debris isn't. Bits of everything that your trailer is made of could be there. This is also very common in residential construction as well.
After a couple of years, you will start finding scale and parts of mineral deposits from pipe wall and the tank in there. If you find gravel fines in your lines, it is time for a filter between the hose and the tank.
"I travel not to go anywhere, but to go. I travel for travel's sake. The great affair is to go". R. L. Stevenson
David Bishop
2002 Winnebago Adventurer 32V
2009 GMC Canyon
Roadmaster 5000
BrakeBuddy Classic II