Hi. My cold water faucet in kitchen sink has started to chatter/knock when I open the
Faucet. Hot water is fine. Seems to be getting worse?

Sounds like a loose washer. What type or brand faucet do you have, pics help

It's a Moen I believe. Two handle with sprayer. I'll attach photo. After I got your response
I found that the fitting for the spout was loose. I tightened it and I'll see if it happens again.
I post here either way. Thanks
Jake

Hey Jake,
Tightening the aerator on the spout won't stop the knock.Shut the water off under then sink and open up the cold water valve, (see image) to remove the cartridge. Check the ports for any trash or debris. Now place a pan over the open valve and turn the water back on to flush out the supply. Reassemble and test. Better now? Good luck, Tom

Tom for my own Curiosity if we have a lose washer on the stem for te angle valve would not give the same problem, Thanks.
Regards,
John

Tom for my own Curiosity if we have a lose washer on the stem for te angle valve would not give the same problem, Thanks.
Regards,
John

Sure would John!
Which is why I had him flush out the supply. I haven't found "seat chatter" or knock in any of the angle stops we have installed but it's always prudent to check. Good advice! Thanks Tom