Tips & Tricks

Turning off your water supply

Typical stopcock valve

If your tap is connected to the mains, it is relatively simple to cut off the supply. Locate and turn off the indoor stop valve, then simply drain the remaining water away by turning on the taps until the flow of water has stopped.

If you’re hot or cold tap feeds off pipes from the cistern (water tank), there should be either a gate valve or mini stopcock available to turn off. The stop valve can be found alongside the cold water tank. When this has been closed, turn on the taps until the water flow has stopped.

Typical gate valve

N.B. If you find that neither the gate valve nor the stopcock is present, then the cistern itself will have to be drained. To drain the cistern you must first prevent water entering the system by switching it off at the mains. Alternatively you can tie up the ball-valve by placing a piece of wood across the tank and tying the arm of the ball-valve to it. Either way, the flow of water will be stopped. The bathroom taps can then be turned on to drain out the remaining water.

If, for some reason, you wish to turn off the outdoor stopcock, you will first need to find it outside of your property. If you cannot locate it, get in touch with your water company. Take of the cover off, and insert the stopcock key. When you have reached the handle at the bottom, turn it clockwise to cut off the flow.


Always know where your stopcock is and make sure it turns the water supply off. If it stiff and seized up look for were your water supply isolates outside the boundary of your property. If this is deep and filled with earth it will be difficult to turn off.

Try to check the stopcock every month or two to keep it working. Try to make sure you understand what type of system you have – Do you have tanks in your loft or do you have a combi boiler. If there are tanks in the loft make sure you know how to isolate the supplies to them, perhaps there are some valves in your airing cupboard?

Pipe Insulation

Keep all pipe work in exposed areas i.e. in the loft or outside insulated to protect it from freezing. Know where to drain your heating system from. This will be a small valve under one or two of the downstairs radiators. It can also be outside. It can save a lot of time looking for it!

Next time you are in the loft check the tanks up there – they should be well insulated and have a secure lid. Check that there is not debris in the tanks (especially dead birds– nice water for brushing your teeth in). This can block the outlet and cause bigger problems further down the line.

If you have a combi boiler, check the pressure and know what it should be when the system is cold. Also know how to repressurise the system if it does drop. If the pressure drops regular you will have to investigate why as there will be a fault there somewhere. Know whether your heating system has had some chemical inhibitor added – this will prolong the life and efficiency of the system.

After the summer you may find some of the Thermostatic radiator valves (TRV) pin may become stuck (the radiator will be cold when the heating is on) Try unscrewing the TRV and gently pulling the small pin upwards with a pair of pliers. This should release it and the radiator should now get hot. The radiator is cold at the top and not at the bottom – generally caused by air. This can be removed by venting / bleeding the radiator. Use vent keys (purchased from most hardware shops) bleed / vent until water comes out.

Leaky taps

If a tap has started dripping, it will probably be just a washer. If is left it can cause damage to the tap which may be irreparable.


Let Plumbcom show you how with our series of video guides.

Closing the stopcock

Craig shows us how to turn off the supply with the stopcock.

Checking boiler pressure

Learn how to check the pressure on a combi boiler.

Another video

Description of the video.

Another video

See more Plumbcom videos on our YouTube channel.

"Very tidy and helpful. The finished article was very good, making my life a lot easier in the bathroom."

Mr Lovell