The free diy home improvement guide with answers to your questions on a wide range of do it yourself projects.


Turning Off The Water

You may need to turn off the water supply in the house if there’s a plumbing emergency, there’s a minor leak, you need to change a fitting or appliance, or you are making some modification to the plumbing. Knowing how to turn off the various parts of a household plumbing system is essential for these projects.

Mains Water Supply – Direct Feed

You can switch off the mains water supply into the house at the main stop cock or stop valve which is usually located under or near the kitchen sink. Turning this off will only isolate those parts of the system which are mains or direct supplies.

If there isn’t a stop valve or you cannot find it then you’ll have to turn the water off at the Water Authority’s stop valve out in the street. These can sometimes be difficult to find but are normally in the pavement just outside the boundary of your property. The cover to these is usually marked. If you cannot find it you may need to ask the Water Authority for your area or, have a chat with the neighbours. Note that these valves may also control water to some of your neighbours so you’ll need to let them know before closing it. Depending on the valve, you may need a special key to switch this off.

Indirect Feed Water Supply

Many parts of the plumbing system are fed indirectly. Water stored in a cold water storage cistern in the loft supplies all the indirect appliances and outlets such as bathroom taps and toilet cisterns. To turn off the water coming from the cold water storage cistern you will need to shut off the valve on the cistern’s outlet supply. If this can’t be done for some reason, you can put a batten across the top of the cistern and tie up the float valve so that it stays closed. Now drain the cistern by opening the bathroom taps or other outlets served by it.

Hot Water Supply

The hot water in your home may be one of several types and you will need to know whether it is direct feed or indirect feed. If you have a combi boiler then the hot water is supplied direct. In this case closing the mains stop valve will close off the water. If you have a hot water cylinder – usually in the airing cupboard – this will be an indirect supply. There will be a valve on the pipe from the cold water storage cistern to the hot water cylinder. Closing off this valve will stop the feed to the cylinder and therefore the hot water at the taps.

Central Heating Systems

If you need to drain down your central heating system to carry out repairs or maintenance, you need to know how to temporarily stop it refilling. On a sealed system there is no new water being supplied unless the filling loop is opened. In its working state, this filling loop remains closed except if the system needs topping up. So if you have to empty this type of heating system it will only refill when the filling loop is opened. On a vented system, the water level is kept topped up by the feed and expansion cistern. Therefore if you drain down this type you will need to temporarily close off the supply from here till you’re ready to refill. Either close off the valve on the incoming pipe to the cistern or, fix a batten across the top and tie up the float valve

Isolating Water to Individual Appliances

Isolating valves are used for many appliances now. It is common to see an isolation valve on the pipe feeding a wc cistern, washing machine or dishwasher as well as on heating runs and pipes feeding bathroom taps. This is a huge advantage as it means that these can be turned off to isolate them without having to close off all other outlets on the same pipe work. Isolating valves may be either screw head operated or of the lever type and require only a half turn to close or open.

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