Why does kitchen faucet whistle when on?

* Loose or worn-out washer: The washer is a small, rubber ring that fits between the faucet stem and the valve seat. If the washer is loose or worn out, it can allow water to leak past and cause a whistling noise.

* Damaged or clogged aerator: The aerator is a small, metal screen that fits on the end of the faucet spout. It helps to mix air with the water, which creates a more even stream of water and reduces splashing. If the aerator is damaged or clogged, it can restrict the flow of water and cause it to whistle.

* High water pressure: If the water pressure in your home is too high, it can cause the water to flow too quickly through the faucet, which can create a whistling noise.

Here are some steps you can take to try to fix the problem:

* Check the washer. If the washer is loose, you may be able to tighten it by hand. If the washer is worn out, you will need to replace it.

* Clean the aerator. Remove the aerator from the faucet spout and clean it with a mild detergent and warm water. Be sure to rinse the aerator thoroughly before reinstalling it.

* Reduce the water pressure. If the water pressure in your home is too high, you may be able to reduce it by installing a water pressure regulator.

If you are unable to fix the problem yourself, you may need to call a plumber for assistance.