The pipes leading to my outdoor faucets squeal at a very high pitched tone when either tap is turned on. As the water flow decreases, the noise changes to a humming sound with vibration. You can feel the vibration if you put your hand on the pipes. These are the only two pipes that do this in my house. The house is around 6 years old and these pipes have been like this since the beginning. The pipe that leads to the front outdoor tap runs in a straight line along the joists for around 15′. The pipe that runs to the rear tap runs straight for 12′ then tuns 90 degrees and runs another 8′ in a straight line right outside. The pipes are clamped onto the joists and secured at the exit point from the foundation. I don’t hear much water hammer, just the squealing. Any ideas? Thanks.