The basin cold water tap in my bathroom over the last week has gone from fully flowing, to half pressure, to a dribble, then to a drip and now nothing comes out.

The 3 other taps in the bathroom work correctly, including the cold water tap on the bath.

Are there a series of simple things to check before calling out a plumber?

  • What type of faucet is it, two knobs, or one?
    – Tester101
    Commented Nov 12, 2010 at 13:00
  • @Tester101 One hole, something like this: goo.gl/rNYUl (it also has a lever plug)
    – Chris S
    Commented Nov 12, 2010 at 14:47
  • The problem was a faulty base of the tap, which was meant the cold tap couldn't be untightened.
    – Chris S
    Commented Nov 13, 2010 at 17:29

6 Answers 6


I could be that the connection between the handle and the actual valve is bad - either it's loose, or stripped.

Is it possible to take the handle off (I'm assuming you have a separate hot & cold handle from the question) to check the condition? Once it's off, you should be able to use a pair of plyers to try to open the valve directly.

If that doesn't work, check the shut-off valve under the sink - if as @aphoria mentions it's something blocking the line, that's another place to check. Turn it off, then back on again, which may dislodge the blockage.


We just had this happen - there was an airlock in the cold water pipe to that tap. As the tab was a mixer (two knobs, one spout), a simple solution is to put your thumb over the end of the spout, open the cold water completely (nothing happens) and then turn the hot water on. Blocking the spout means the hot water is routed back up the cold pipe, eliminating the air lock.

Use a cloth/rag if your hot water is too hot to keep your thumb over the end - it takes a minute or two.

  • 2
    My cold water was not running because of an air lock. My faucet was like the one described above (one spout, two handles). I had trouble blocking the spout with my finger and tried several different bottle caps to force the water into the cold supply, but the winner was a wine cork. After letting the water run for just a few seconds the air was out of the cold water supply and it works like a charm!
    – user14849
    Commented Aug 31, 2013 at 19:26
  • 1
    Thank you so much for pointing out that it takes a minute or two. I’ve tried this before with no success, because I didn’t realize it took a minute. I just now blocked the faucet with my finger for a minute or so and it all cleared up!
    – mattgately
    Commented Feb 15, 2021 at 21:06

There may be some sediment blocking the line. Many faucets have a small filter right at the end (where the water comes out) that you can unscrew and clean out. Check that first.


I just had a problem with my cold water faucet in my bathroom sink. It quit working out of nowhere! My shower faucets worked just fine. I put a plastic bag over my sink faucet with a little hot water running. Pretty much suffocating my faucet. Gave it a few seconds and now the cold water runs back!

  • That actually worked! I would have never guessed this one. Thanks.
    – dushyantp
    Commented Jan 3, 2019 at 21:59

It could very well be a frozen pipe if you live in a cold area.

  • 2
    If it stops overnight, yes. But from the description of the OP's problem, losing pressure over a few days, it sounds more like a sediment blockage or bad valve. If you get a trickle from a freezing pipe, it should speed back up as water flows through and melts any ice that's formed.
    – BMitch
    Commented Feb 16, 2015 at 15:58

For us it was a frozen pipe. We actually noticed the water was not running and immediately found a spot where the pipe was close to the outer wall in the basement where insulation was missing. We were lucky and used a blow dryer to heat the pipe and we now will be insulating around it. Glad the pipe did not burst!

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