Brown or orange particles are typically rust particles that have broken off the inside of your water pipes or the SUB water mains. These particles are very hard, irregular in size and shape, and can be several different colors (including black). They consist of mostly iron and are not a health hazard but they are a nuisance if they clog washing machine screens, showerheads, or faucet aerators.
Another common cause of brown or orange particles in the water is a broken water softener. A water softener contains many small, round beads (or resin) for softening water. The beads will be uniform in size, typically the size of fish eggs, and are brown or orange. The mechanism that keeps these beads in the tank can break, releasing them into your water. Call your service agent for repairs.