How to Fix a Frozen Sink Shut-Off Valve and Get It Moving

Locate the main water valve and turn it off before tackling a frozen sink shut-off valve. Don’t skip this step, as pipes can burst or leak while you’re trying to work, which can turn a fairly simple fix into a bigger problem.

Once the water is off, gently try to turn the sink shut-off valve in both directions. Start by twisting it a little clockwise and then counterclockwise. If you have difficulty getting a good grip, use a cloth or gloves to help. 

Repeat this process, and the valve may loosen and become easier to turn. If that’s the case, keep working the valve until it can freely open and close. However, don't force it if it doesn’t get easier to move.

Sometimes loosening the packing nut (located below the valve’s knob or handle) can loosen the valve. It’s worth trying to loosen this nut when dealing with a frozen valve, even though this is more likely to work if it’s stuck due to mineral deposits. 

A frozen valve may need to be thawed. Heat can also help if extra gunk or minerals are locking up the valve. Use a hair dryer to blow hot air directly on the valve for five to ten minutes. Then, gently twist the valve clockwise and counterclockwise to check it. 

You might need to wear gloves if the valve has gotten hot. You can apply the hair dryer several times and check the valve for movement every 10 minutes.

If a hair dryer doesn’t get things moving, try pouring boiling water over the valve. However, only use boiling water on metal or ceramic pipes, as plastic pipes can get damaged.

First, place a bucket underneath the valve to catch the dripping water. You can also dip a cloth into the hot water and hold the cloth to the valve to reduce the risk of making a mess.

After applying heat and using your hand to test the valve, you might need to gently tap the valve with a hammer. Simultaneously, try turning the valve to see if it’s thawed and loosened. To prevent future freezes, keep an eye on the temperatures at which pipes freeze and use precautions to keep water flowing and pipes warm.

Penetrating oil can loosen and lubricate the valve as it seeps between seams. If the main problem is a frozen valve, you might not need penetrating oil, but it’s worth trying if the previous steps haven’t worked.  

Apply the penetrating oil and let it sit on the valve for 30 to 60 minutes or the time recommended by the manufacturer. Give the valve a tap with the hammer to check for movement. You can also apply the hair dryer again at this point.

If the valve closes and opens, you can turn on the main water valve and try turning on the water to the sink. Have a towel ready in case there’s a leak. Once you get the valve moving, consider how to keep pipes from freezing in the future.