I have a friend who lives in an apartment with terrible water hammer problems which the management is unwilling to fix.
I'm curious if there is a product or device that would attach, for instance, to a faucet with the faucet on that would act as a water hammer arrestor. I haven't seen anything like that, and I expect that even if it did exist it wouldn't help too much as it's not near the source of the problem, and the pipes would still rattle, but even if it helped a little he might get more sleep.
Right now it feels like someone's hitting his walls with a sledgehammer a few times an hour as other people in the building use the supply.