Black particles can come from 2 common sources: a broken water filter, a degrading faucet washer or gasket, or a disintegrating black rubber flexible supply line hose (for a water heater, washing machine, or kitchen faucet, etc.).
- If the particles are very hard, similar in size and shape, and look like large coffee grounds, they are probably granular activated carbon (GAC) particles from the inside of a GAC water filter that you have installed. Replace the filter cartridge or consult with the manufacturer or the vendor who sold it to you.
- If the particles are solid but rubbery in texture, they could be pieces of an old disintegrating faucet washer or gasket. If this is the problem, the particles would likely only be present at one faucet and that faucet may be leaking. Replace the faucet washers and the packing at the ends of the supply lines.
- If the particles are small black particles that can be easily smeared between two fingers, they are probably from the inside of a flexible hose. These black rubber hoses are covered with a braided stainless steel mesh. Over time, the chlorine in the water causes the rubber to break down. Replace the hose, ideally with a liner that is identified as chemical or chlorine resistant. Black rubber hoses typically have a one-year warranty while the more chemical resistant hoses have a 5-year warranty.