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The Stopcock Guide


The water stopcock is often referred to as the water stop valve and is used to shut off the water supply to your house. If you plan to carry out any work involving water, you will want to ensure that the stopcock is closed.

Although they aren’t used very often, they are a crucial component of any water system. For this reason alone, it’s advised that you regularly check the stopcock to ensures it’s working properly. If you notice that it’s not working as it should, do not hesitate to call one of our Cardiff plumbers to fix the issue.

To help with some of the questions we get asked on a regular basis, we have answered the most common below.

Where is my Stopcock?

If you have just moved into a property, you may not know where the stopcock is located. They look like a tap but don’t have an outlet spout and it sits between two lengths of pipe. The locations vary from property to property but the most popular places to install a stopcock include:

  • Underneath the kitchen sink
  • Inside a kitchen cupboard
  • In the bathroom or downstairs toilet
  • Garage or utility room
  • Under the stairs
  • Near the front door or under the floorboard

Operating the stopcock should be effortless but if it hasn’t been used for a while, it may be ceased. If this is the case, you may want to give us a call to replace the faulty unit.

Should Stopcock be Fully Open?

Keeping the stopcock fully open will cause no major harm but it can allow limescale to buildup in the spindle. We recommend that you have turn it fully open and then back by half a turn, which should prevent the spindle jamming up. With regular usage, limescale wouldn’t build up but 9 times out of 10, the stopcock isn’t used for long periods of time.

Stopcock is Leaking

Depending upon the severity of the leak, you may be able to prevent any water damage with a temporary fix. If it’s leaking from the gland, you may be able to simply tighten it up to slow down the leak. If the water leak is coming from the nuts, the use of a PTFE or plumbing paste may be your best option. If the stopcock is leaking from the main body, you should call a plumber as soon as possible to avoid the leak becoming far worse.

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180 Ffordd James McGhan, Cardiff, CF11 7JU
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