A water faucet squeal is a very loud, screeching sound that is unmistakable but not difficult to understand or fix. The squealing sound is usually due to one of two things, either a loose part or a plumbing fixture. For the experienced handyman, this problem only takes about an hour to fix if you have the right parts.
A loose washer inside the faucet often causes a screeching or squealing sound. The noise occurs when water rushes past the washer making it flutter or flap in the water stream. The flapping creates a vibration that is very fast and sounds like a squeal. This same problem also sounds like a horn or a wailing sound in some faucets depending on how loose the washer is and what other parts the washer comes in contact with.
The stem is the part inside the handle of the faucet containing the valve to shut off or turn on the water. A worn-out stem often leads to several problems including a loose washer or other loose internal parts that will flap around when water pushes through the stem. In either case, the loose parts scrape against metal inside the handle and cause a squealing sound that is ear piercing at times. The solution to this issue is replacing the entire stem with a brand new part. This job requires a ball socket wrench and a replacement stem for your faucet.
High Water Pressure
High water pressure will cause squealing sounds inside of faucets along with a host of other noises. The faucet is only designed to withstand and work within a certain range of water pressure. Increased pressure forces water through the inlets and spout at a faster rate than normal, causing compression sounds similar to squealing and screeching. If debris is lodged in the pipes or faucet, water rushing over the debris also causes squealing when water pressure is high.
Hot Water Squealing
If the squealing sound only occurs during the use of hot water, the issue is probably associated only with your hot water pipes or faucet parts. Either the stem valve or washer on the hot water side is loose, or something is lodged inside of the hot water pipe. Another possibility is pipe stretch. When the hot water enters the pipes, it causes expansion due to the temperature increase, and metal pipes stretch against their brackets, which causes a short squealing sound to occur. Replacing your pipe brackets and supports or pipes is the only way to resolve this issue.