Black particles that clog a water faucet could originate from different sources. Although the problems do not create a health hazard, they are bothersome, and you should avoid drinking or cooking with water that has the particles in it. Through troubleshooting, you can usually identify which one of the four usual suspects is behind the appearance of black particles.
If you examine the small black particles and notice that they are irregular in both size and shape in addition to being very hard, they are likely small pieces that have broken off from the insides of pipes. These pipes could be a part of your dwelling's own plumbing system or part of the city's main pipes. If the particles are from the city pipes, the particles are usually found in the cold water. The corroded pipes are usually made of either iron or steel. If there has recently been a shutoff by the main water company, the black particles in the water when it is turned back on may result. In addition, the water coming through the faucet may be discolored as well.
Disintegrating Washers or Rubber
The black particles in water from a specific faucet could also be the result of a black washer or gasket inside the faucet itself that has degraded over time. These soft particles are likely rubbery, also. To locate and inspect the washer, first turn off the faucet's water supply by twisting the shutoff valves on the wall underneath it, completely to the right. The particles may also come from the disintegration of the black rubber portion of the faucet's flexible, stainless steel supply hoses. The disintegration is often caused by disinfectants used in the city's water supply. Replace these supply lines with others that don't have rubber.
Corroded Water Heater
If the black particles are only found in the hot water coming from the faucet, you can rule out the particles coming from the city water supply. Another possibility is that corrosion inside the water heater is depositing the debris that breaks away to flow through the faucet water. Follow the manufacturer's instructions for maintenance on the water heater. Flushing out the water heater, as well as the faucet water lines, may get rid of the particles.
Broken Water Filter
If you find that the black particles are very hard and also fairly uniform in size, they could come from the inside of a broken water filter. These particles are granular activated carbon. Replace the filter cartridge found inside the filter according to the manufacturer's instructions in the owner's manual.