Water Supply Valve Under Kitchen Sink Is Leaking – How To Fix?

My water supply valve under the kitchen sink leaks. I am replacing the faucet in my kitchen. I have the faucet installed in the sink but not connected to the hot and cold water. The hot and cold water supply under the sink is turned OFF at the valves. The cold water supply line from the wall is dripping water slowly. It is dripping from the cold water supply valve under the sink that the faucet will be connecting into. If I have the cold water valve completely turned OFF, could it be that the cold water valve under the sink is faulty and leaking? Do I need to shut off the main water supply to my complete house and remove and replace the water inlet valve under the kitchen sink?

Replacing Kitchen Sink Faucet - Water Valve Under Sink Is LeakingWater Supply Valve Under Kitchen Sink Faucet Is Leaking – How To Fix?

  • It may just be excess water left over, remove all the water so it is 100% dry. Check the valve very carefully for about 30 minutes with a flashlight and if you find it is leaking then remove and replace it. You will need to turn the main water valve OFF to your home if you replace the cold water valve under your kitchen sink.
  • If you see water leaking out, this means the valve is leaking. It is very common for this to happen. To stop the leak or replace the value you would have to cut off the main water supply. This type of leak is so minor you can replace the faucet before the dripping becomes an issue. Once the water line is connected it should not be a problem.
  • You can also try turning off water supply to house, remove the cold water inlet valve, clean it so there is no corrosion, then wrap it with plumbers tape on ALL the threads. This MAY stop the leak, however a new valve is around 10 US dollars so if you are going to go through the trouble of turning off water to your house, you may as well replace the valve with a new one.

If you do have to replace the water supply valve under your kitchen sink:

  1. Turn off main water supply to house.
  2. Place a throw away towel or a bucket under the valve.
  3. Remove the valve with a wrench.
  4. Some water should come out so be prepared.
  5. Take the valve to your local home improvement store or go on Amazon and match up the threads as some have different threads.
  6. Buy some plumbers tape.
  7. Once you have the correctly threaded water supply shut off -wrap the plumbers tape around the threads to give it a good seal.
  8. Thread the new water supply valve into the wall to the proper angle and torque.
  9. Turn the water supply valve under the sink OFF.
  10. Turn the home water supply back on.
  11. Attach the water line from the faucet to the water supply shut off valve using plumbers tape.
  12. Once tight and in place, turn the valve ON and test the kitchen faucet.
  13. There should be NO leaks and all should be good.
  14. Good job, you have fixed your leak!

Here are the parts you will need to fix water supply kitchen sink leaking in cabinet:

You can search Google for parts to fix your water supply valve.

Water shut off valve for under kitchen sink - replacement for leaksWater shut off valve for under kitchen sink – Replacement for leaks


Pipe Water Sealant Plumbers Thread Seal TapePipe Water Sealant Plumbers Thread Seal Tape


Water Supply Valves - Compression Inlets For Fixing Water Leaks Under SinksWater Supply Valves – Compression Inlets For Fixing Water Leaks

Videos to show how to remove and replace or fix water supply valve under kitchen sink…

How to Fix a Leaky Shut-Off Valve in Seconds


How to Remove and Install a Water Shut off Valve for Beginners


How to Repair a Leak Under the Sink



Have a question or need help? Please let us know your issue with your kitchen water supply valves. We will assist you and help you to fix the issue.

1 thought on “Water Supply Valve Under Kitchen Sink Is Leaking – How To Fix?”

  1. I’ve noticed the water coming out of my sink isn’t as powerful of a flow as it used to be. I think it might have something to do with my water well and I will have to hire a professional to come repair it.

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