A kitchen faucet washer is a small seal that holds water tight to prevent leaks at the base of the faucet. Eventually, these washers will wear out from continuous use and mineral deposits on them, and cause leaks, which waste water and inflate utility bills. Once leaks occur, the old washer needs to be removed and a new one installed to seal once more, which is necessary for faucet wa... https://www.partsfe.co.uk/plumbing-parts/washer