When I turn on any household faucet, specifically the cold water, it makes noises as if their may be air in the line. What could it be and how do I fix it?

If your faucet has washers and seats I would suspect that the retaining screw came loose and the washer's vibrating against the seat as the water rushes by. The solution would be to shut the water off and open up the faucet. Check the washer and tighten if loose. Before you button the valve back up turn on the cold water for a minute to flush out the valve body and supply. Good luck, Tom

bredin01 disagrees: My question is not isolated to one faucet.
Hey! Can't win them all! Explain about the "air in line" noise. Does air come out of your faucets? Do they sputter and spit at you? Are you on a pump or city water? If on city water do you have a pressure reducing valve? Back to you,

Bred, you stated "household faucet" and that sure sounded like one faucet to me. We can't always guess that info is not complete. I was going to suggest that the bad washer was at your main but that would make noise if the hot were also involved. Back to you for more info.

Yes, air seems to come out of the faucets in a spit and sputter manner and I am on city water. Not sure about the pressure reducing valve. Please advise.

Just the cold and never the hot, right?

Yes

Is there a sprinkler system? Have you asked your neighbors if they have the same problem? Think! Is there anything added to your water system that could interject air into it? A pressure reducing valve sets right after the water service enters your home. Its purpose is to reduce the higher PSI in the city main down to a acceptable house pressure. Regards, Tom

No sprinkler system. No problem with neighbors. Nothing added to water system. There appears to be a pressure reducing valve. Please advise.

I think I might have it. If there was something vibrating in the pressure reducing valve it would affect the cold water in spurts and jerks but the hot water would be buffered by the water heater and not be affected. Have the PRV valve checked out. Good luck, Tom

Expert detective work even after you got a reddie. I was thinking PRV but didn't think about how the hot water tank would buffer the spurts. Great job Tom.

I have hot water on the top floor and full water supply on the ground floor, but nothing in the middle. Help

I have hot water on the top floor and full water supply on the ground floor, but nothing in the middle. Help
What fixtures are affected on the middle floor? No pressure at all?
Let me know, Tom