Plumbing Question in Bathroom

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.