General advice FAQ
general advice
- If the water supply goes off due to a burst main do I need to turn off my central heating?
- How do I turn my water off?
- What if I can't turn off my water supply?
- Why does my water flow slowly upstairs when someone opens a tap downstairs?
If the water supply goes off due to a burst main do I need to turn off my central heating ?
You can usually continue to use the central heating.
The majority of central heating systems are operated by a "closed" system. This means that the radiators and pipework are filled up with the same water that is reheated and travels through the boiler and round the radiators time and time again. Most systems have a small header tank above the system. This provides water automatically if any is lost through bleeding the radiators or minor condensation. Usuallly no more than half a pint (250ml) of new water is used by a system in any one year.
Customers that have "multipoint" or "instantaneous" boilers can also continue to use their heating. A coil inside the boiler ensures that central heating can operate without an incoming water supply.
How do I turn my water off?
You need to find your 'internal stop tap' (IST). IST's are usually found in the kitchen or downstairs cloakroom/bathroom, often under a sink, but they can be anywhere on the ground floor of your property. As a rule they are only a few inches/centimetres from floor level and are situated on a pipe that comes through the floor.
One way of locating the IST is to look under your kitchen sink and follow the pipe that connects to the cold tap away from the sink. This should lead you to the main pipe supplying the cold water into your home and you should find a IST on the pipe close to where it enters the property. If you live in a flat the IST can be in ducting inside your flat, or behind an access shaft in the communal area. In some flats the IST is situated similarly to that of a IST in a house (see above).
what if I can't turn off my water supply?
IST's are used infrequently and so can get stiff to the point that they cannot be operated. In the event of an emergency where the IST will not operate a Controlling Stop Tap (CST) can be used to stop the supply. Most CST's belong to Severn Trent (although in some cases private CST's exist within gardens etc) and it is strongly advised that customers do not attempt to operate them. The CST is in a chamber around 760mm (2ft 6in) deep and therefore needs a 'Stop Tap' key to enable operation. Customers may risk serious injury through broken glass, needles and debris that may have been deposited in the chamber by others.
Most plumbers have stop tap keys. In an emergency situation where a property is flooding and you cannot operate the IST or contact someone to operate the CST, please ring our 24 hour Operational Contact Centre on 0800 783 4444. We will arrange for emergency isolation of your supply as soon as possible.
Why does my water flow slowly upstairs when someone opens a tap downstairs ?
Water travels through pipes because an external force is introduced to it. This force is usually caused by gravity or by pumps. As water travels through the pipes it loses some of its energy because of 'drag' caused by friction between the pipe wall and the water.
In some properties, when a tap or 'water using appliance' at lower levels is opened or in use, it consumes the energy within the water flow. This sometimes means that the available flow and pressure at higher levels, such as upstairs, becomes impeded and there is less pressure and flow.
Some customers, particularly in newer homes, don't tend to notice this problem as the pipes are sized to cope with draw offs taking place at more than one point at once. However, in some properties with older plumbing systems, it can be quite noticeable. This type of issue is largely down to each property and its individual plumbing. If you contact a registered plumber they can advise on the matter further.