My washing machine causes a water hammer banging. My kitchen faucet does it sometimes, but not always. I purchased two Watts water hammer arrestors that go in the water line. See picture below. I plan to put one of them on both the hot and cold feed lines.
My question is: Should I put the arrestors as close as possible to the washer, or put then further upstream so that I stop the water hammer from the kitchen sink as well (that would be about 20 feet away from the washer feed).
My unprofessional opinion is that the closer to the washer the better.